Merge pull request #28 from dillardblom/release-1.0.2

Release 1.0.2

.github/FUNDING.yml

@@ -0,0 +1 @@
+custom: ["https://www.ensembia.com"]

.github/ISSUE_TEMPLATE/experience.yml

@@ -0,0 +1,56 @@
+name: Experience report
+description: Tell us how NG Backup works for you, also when everything went fine.
+title: "Experience: "
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thanks for trying NG Backup! Reports of what works are just as useful as bug reports:
+        they tell us which setups are tested. Please leave out host names, user names and keys.
+  - type: dropdown
+    id: location
+    attributes:
+      label: Backup location
+      multiple: true
+      options:
+        - S3 / S3-compatible
+        - SFTP
+        - WebDAV
+        - SMB/CIFS
+        - FTP
+        - Swift
+        - Local path (disk, NFS mount, ...)
+    validations:
+      required: true
+  - type: input
+    id: provider
+    attributes:
+      label: Storage provider (optional)
+      placeholder: e.g. Hetzner Storage Box, OVH, Backblaze B2, own NAS
+  - type: input
+    id: setup
+    attributes:
+      label: Nextcloud version and setup
+      placeholder: e.g. 32.0.1, AIO / Docker / bare metal, PostgreSQL / MariaDB
+  - type: input
+    id: size
+    attributes:
+      label: Rough size of the backup
+      placeholder: e.g. 50 GB, 200,000 files
+  - type: checkboxes
+    id: tried
+    attributes:
+      label: What did you try?
+      options:
+        - label: Full backup
+        - label: Incremental backup
+        - label: Verify
+        - label: Restore of files or folders
+        - label: Full restore on another server
+  - type: textarea
+    id: notes
+    attributes:
+      label: How did it go?
+      description: What worked, what was unclear, slow or broken.
+    validations:
+      required: true

.github/workflows/ci.yml

@@ -17,6 +17,8 @@ jobs:
         php: ['8.2', '8.3', '8.4']
     steps:
       - uses: actions/checkout@v4
+        with:
+          persist-credentials: false
       - uses: shivammathur/setup-php@v2
         with:
           php-version: ${{ matrix.php }}
@@ -29,6 +31,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
+        with:
+          persist-credentials: false
       - uses: shivammathur/setup-php@v2
         with:
           php-version: '8.2'
@@ -37,6 +41,20 @@ jobs:
       - run: composer install --no-interaction --no-progress
       - run: composer psalm
 
+  frontend:
+    # Builds the admin page, so a broken Vue component fails CI instead of showing up after a release.
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          persist-credentials: false
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '22'
+          cache: npm
+      - run: npm ci --no-audit --no-fund
+      - run: npm run build
+
   integration:
     # Full round trip (key, kit, location, backup, incremental, restore modes, database dump and
     # restore, retention, trash) on a fresh Nextcloud per version and database.
@@ -48,6 +66,8 @@ jobs:
         database: ['sqlite', 'mariadb', 'pgsql']
     steps:
       - uses: actions/checkout@v4
+        with:
+          persist-credentials: false
       - name: Round trip on Nextcloud ${{ matrix.nextcloud }} / ${{ matrix.database }}
         run: tests/integration/matrix.sh "${{ matrix.nextcloud }}" "${{ matrix.database }}"
 
@@ -58,5 +78,67 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
+        with:
+          persist-credentials: false
       - name: Round trip against S3 and SFTP
         run: tests/integration/targets-matrix.sh
+
+  integration-user:
+    # Per-user backup/restore via user_migration (occ backup:user:backup / backup:user:restore),
+    # an optional dependency installed from the app store. It calls user_migration's internal
+    # UserMigrationService, whose API can change between Nextcloud versions, so this runs on every
+    # supported version (not the database, which the main integration job already covers).
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        nextcloud: ['32', '33', '34', '35']
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          persist-credentials: false
+      - name: Set up a fresh Nextcloud instance
+        run: |
+          docker run -d --name ngbu -e SQLITE_DATABASE=nextcloud -e NEXTCLOUD_ADMIN_USER=admin \
+            -e NEXTCLOUD_ADMIN_PASSWORD=admin-user-roundtrip -e NEXTCLOUD_TRUSTED_DOMAINS=localhost \
+            -v "$PWD:/var/www/html/custom_apps/ng_backup:ro" nextcloud:${{ matrix.nextcloud }}-apache
+          for i in $(seq 1 90); do docker exec -u www-data ngbu php occ status 2>/dev/null | grep -q "installed: true" && break; sleep 4; done
+          docker exec ngbu chown www-data:www-data /var/www/html/custom_apps
+      - name: Per-user backup/restore round trip on Nextcloud ${{ matrix.nextcloud }}
+        run: tests/integration/user-roundtrip.sh "docker exec -u www-data ngbu" /var/www/html/data
+
+  integration-full-restore:
+    # Disaster recovery (occ backup:restore:full) on a SECOND, fresh Nextcloud instance that
+    # never saw the first one, sharing only the backup location. Does not depend on the database
+    # beyond what the main integration job already covers, so this runs once, on one NC version.
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          persist-credentials: false
+      - name: Full restore round trip
+        run: tests/integration/full-restore-roundtrip.sh 35-apache
+      - name: Full restore round trip on PostgreSQL, with Mail (foreign keys) and a disabled app
+        run: tests/integration/full-restore-roundtrip.sh 35-apache pgsql
+      - name: Full restore round trip on MariaDB, with Mail (foreign keys) and a disabled app
+        run: tests/integration/full-restore-roundtrip.sh 35-apache mysql
+      - name: Full restore of a backup made by 1.0.0-rc.1 (no table structure) on PostgreSQL
+        run: tests/integration/full-restore-roundtrip.sh 35-apache pgsql legacy
+      - name: Full restore of a backup made by 1.0.0-rc.1 (no table structure) on MariaDB
+        run: tests/integration/full-restore-roundtrip.sh 35-apache mysql legacy
+      - name: Full restore over SFTP on PostgreSQL, reading packs ahead on several connections
+        run: tests/integration/full-restore-roundtrip.sh 35-apache pgsql sftp
+      - name: Full restore of a MariaDB backup onto PostgreSQL (ID counters after the data)
+        run: tests/integration/full-restore-roundtrip.sh 35-apache mysql to-pgsql
+      - name: Full restore of a PostgreSQL backup onto MariaDB
+        run: tests/integration/full-restore-roundtrip.sh 35-apache pgsql to-mysql
+      - name: Full restore of a PostgreSQL backup onto SQLite
+        run: tests/integration/full-restore-roundtrip.sh 35-apache pgsql to-sqlite
+      - name: Full restore of a MariaDB backup onto SQLite
+        run: tests/integration/full-restore-roundtrip.sh 35-apache mysql to-sqlite
+      - name: Full restore of a SQLite backup onto PostgreSQL
+        run: tests/integration/full-restore-roundtrip.sh 35-apache sqlite to-pgsql
+      - name: Full restore with a damaged database dump (--salvage)
+        run: tests/integration/full-restore-roundtrip.sh 35-apache sqlite salvage
+      - name: Full restore with a damaged and a missing pack (--salvage)
+        run: tests/integration/full-restore-roundtrip.sh 35-apache sqlite salvage-files

CHANGELOG.md

@@ -2,9 +2,485 @@
 
 All notable changes to NG Backup are documented here. The format follows
 [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); versioning follows the stages in
-`PLAN.md` section 9. The `<version>` in `appinfo/info.xml` is plain SemVer-numeric (Nextcloud's
-own `info.xsd` doesn't allow a `-alpha`/`-beta`/`-rc` suffix there); the stability stage is instead
-carried by the git tag, the release, and this file.
+`PLAN.md` section 9. The `<version>` in `appinfo/info.xml` is plain SemVer-numeric on purpose:
+the app store accepts a `-beta` suffix, but Nextcloud servers then only offer the release on the
+beta/daily update channel, which would hide the app from most admins. The stability stage is
+instead carried by the app description, the git tag, the release, and this file.
+
+Each heading starts with that `<version>`, once: the app store shows a release the section(s)
+whose heading starts with its `x.y.z` and ignores anything after it, so `## [1.0.0-rc.6]` would be
+shown under 1.0.0. The git tag of a release candidate goes after the date.
+
+## [1.0.2] - 2026-11-06
+
+### Added
+- A warning on the admin page and in `occ backup:status` when background jobs do not run on a
+  system cron, or the cron stopped, with a link to how to set one up. Backups, also the scheduled
+  ones, need it (#13).
+- Without a working system cron, a backup started with "Back up now" moves on while the NG Backup
+  page stays open (#13).
+- `--salvage` for `occ backup:restore` and `occ backup:restore:full`: restore whatever can be
+  read when a backup is damaged. Files that cannot be read or decrypted are left out and listed,
+  and the command exits with code 2. When the database cannot be restored, `backup:restore:full`
+  leaves the fresh database as it is and puts the data directory and config of the backup in
+  `ngb-salvage-<snapshot>` in the data directory, to put back by hand.
+- The trash of restore points has a tab of its own, "Bin", instead of being shown below the
+  backups.
+
+### Changed
+- A backup in its database phase shows how far it is, for example "running (db: 47/183 tables)",
+  and one that has not moved for 15 minutes says "waiting for background jobs" with when it last
+  took a step. Before, it only said "running (db)", which looked the same as being stuck (#13).
+- Full restores from S3 read the packs ahead, eight ranges at a time, as restores over SFTP do
+  since 1.0.0-rc.4. Over SMB the packs are read in 8 MiB reads instead of 1 MiB: over a line with
+  a 130 ms round trip, reading was four times faster in a test (18 instead of 4.5 MiB/s).
+- Over SMB the index files, which a new server reads in `backup:target:add`, take fewer round
+  trips: from Canada to a Hetzner Storage Box (130 ms), 0.66 instead of 1.05 s per file, so about
+  5 instead of 8 hours for the 27,000 index files of a 1 TB repository.
+- `occ backup:restore:full` that runs again after it stopped (`--force`) goes on where it was: data
+  files already in place with the size and modification time of the backup are left, and only
+  the rest is read from the location. Before, a stopped restore of 1 TB started over.
+
+### Fixed
+- A full restore over SMB could hang at 100% CPU when the connection to the server dropped: a
+  failed read was counted as data. It is now read again over a new connection. Found in a
+  disaster recovery test of 1 TB from Canada to a Hetzner Storage Box, after 392 GiB.
+- The read-ahead folder of a restore that was killed while it wrote is removed by the next run;
+  it kept one file of up to 8 MiB.
+- `occ backup:target:add` only estimates the time left for reading the index once enough of it
+  is in. The first file also carries the time to connect, which made it say "about 642 min left"
+  for something done within a minute.
+- A restore that stops because a file is gone from the location now points at `--salvage`, as it
+  already did for damaged data.
+
+### Known issues
+- Empty folders are not backed up or restored; to be fixed in 1.0.3 (#27).
+
+## [1.0.1] - 2026-11-01
+
+Fixes for what was reported after 1.0.0 (#22, #24) and small improvements. Nothing changes in
+your backups or settings.
+
+### Added
+- `occ backup:user:list [location] [user]` shows the user exports on a location, with the manifest
+  path `backup:user:restore` expects. Before, that path was only printed once by
+  `backup:user:backup` (#22).
+- A "Docs" tab on the admin page, with links to the how-to, the disaster recovery guide and the
+  roadmap. It also shows before the backup key is set up.
+- A label for a backup started with "Back up now" (optional; `occ backup:run -l` already had one).
+  It shows with the restore point.
+- An explanation in the trash of restore points of what "removed by retention policy" means: the
+  policy keeps the newest restore points and the last one of each recent day, week and month, and
+  moves the others to the trash, where they can be brought back until they are deleted
+  permanently. `occ backup:trash` says the same below its list.
+
+### Changed
+- `occ backup:status`, `backup:list`, `backup:trash` and `backup:browse` show times in the time
+  zone of the daily schedule and name it, as the admin page shows them in the administrator's.
+  Before, they showed the server's UTC, which read as a wrong start time.
+- The admin page no longer says NG Backup is in beta.
+- `occ backup:user:restore` also takes a user id instead of the manifest path, when that user has
+  exactly one export on the location. With more, and for a manifest path that is not on the
+  location, the error lists that user's exports; for a user without exports it names the
+  expected form (#22). Before, `backup:user:restore <location> <uid>` only said "is not a
+  recorded user export for this location".
+
+### Fixed
+- An SFTP location with an RSA key in OpenSSH format ("BEGIN OPENSSH PRIVATE KEY") stopped
+  working after an upgrade to Nextcloud 35 with "Unable to read key", and such a key could not be
+  added there at all (#24). The "Private key" field on the admin page is a single line, so a
+  pasted key lost its line breaks; Nextcloud 34 still read it, Nextcloud 35 reads keys with a
+  stricter library. The line breaks are now restored before the key is used, so a stored location
+  works again without re-entering it.
+- A full restore onto SQLite could stop at once with "database is locked" when another process
+  wrote to the database just as the restore began (a background job that was already running).
+  The restore now takes the write lock first and waits for the other process instead. The
+  full-restore test on SQLite runs with a second process writing alongside.
+- `occ backup:restore ... --to-directory` of a single file restored nothing ("Restored 0
+  files"); only a folder worked. A path to a file now restores that file.
+- A restore that was stopped (a crash, a timeout, a restart) left its half-written temporary file
+  (`<name>.ngb-restore-<id>`) next to the file it was restoring, and a `files:scan` then showed it
+  in Files. A restore now removes such leftovers in each folder it writes to.
+- The app store showed the notes of every release candidate under 1.0.0, because their headings
+  started with "1.0.0-rc". Each heading now starts with the app version of that release.
+
+## [1.0.0] - 2026-10-29
+
+First stable release. NG Backup makes encrypted, incremental backups of your whole Nextcloud
+(files, database and configuration) to S3, SFTP, WebDAV, SMB and other storage, and restores them
+from the web interface or with occ. Disaster recovery has been tested on real installations; see
+"Tested disaster recoveries" in the README, and read "Known limitations" before you rely on it.
+
+The code is the same as 1.0.0-rc.6 (app version 0.9.12): updating from it changes nothing in your
+backups or settings.
+
+## [0.9.12] - 2026-10-24 (1.0.0-rc.6)
+
+Sixth release candidate for 1.0.0; the app version is 0.9.12. Fixes from two disaster recovery
+simulations and a user report.
+
+### Fixed
+- The daily backup time was taken as UTC (Nextcloud runs PHP in UTC): 03:00 ran at 05:00 in
+  Berlin (#19). The time is now saved with the administrator's time zone and shown with it. A time
+  saved before is converted once to the zone of the server or an administrator, so it shows as it
+  effectively ran (02:30 UTC becomes 04:30 Europe/Berlin in summer) and nothing moves.
+- A full restore over SMB stopped after 17 hours with "Decryption failed": a read over a long
+  line handed out wrong bytes (the backup itself was fine, the same files restored identically
+  afterwards). A blob that does not decrypt as first read, of a file or of the database, is now
+  read once more on a request of its own, and only a second failure stops the restore.
+- A full restore onto MySQL/MariaDB stopped with "Incorrect string value" when it created a table
+  (of an app that is not installed here) whose rows hold emoji or other 4-byte characters: the
+  table got 3-byte utf8. Tables the restore creates now get this installation's character set and
+  collation (utf8mb4). Found in a disaster recovery simulation onto MariaDB.
+
+### Changed
+- The admin page uses more of the screen (sections up to 1400 pixels instead of 900), so the
+  list of backup runs fits without scrolling sideways.
+- README: a roadmap, the tested disaster recoveries, measurements for OVH S3, the Storage Box over
+  SFTP and SMB, how to build the SMB extension when PECL is down, and what works without shell
+  access. The guide lists shell access among what you need.
+- The full-restore integration test checks a 4-byte character in a table the restore creates, and
+  retries app installs from the app store.
+
+## [0.9.11] - 2026-10-22 (1.0.0-rc.5)
+
+Fifth release candidate for 1.0.0; the app version is 0.9.11. A full restore of 1 TB over SFTP
+stopped after 13 hours with "Blob not in index"; the backup itself was fine.
+
+### Changed
+- README and app store description: NG Backup needs background jobs on system cron, with how to
+  set that up (issues #13, #17).
+
+### Fixed
+- A full restore no longer stops with "Blob not in index" after a pack could not be read for a
+  moment. Reading the index again then got an empty listing (from a connection the location had
+  dropped) and emptied the index. Reading the index again now only adds, an empty listing of a
+  location that has an index is an error instead of an empty index, and a pack that could not be
+  read is read once more before the restore gives up.
+- After a full restore of a MySQL/MariaDB or SQLite backup onto PostgreSQL, new files, users or
+  activities could not be added ("duplicate key", "File entry could not be inserted"): such
+  backups record no ID counters, and they stayed at 1. Every counter of a restored table now goes
+  after its data. Found in a disaster recovery simulation of 138 GB from MariaDB to PostgreSQL,
+  where all 15,772 files and every count were identical.
+- A full restore now runs in maintenance mode: a background job, a page visit or a user writing
+  into the instance meanwhile could collide with restored rows ("duplicate key") or be lost. It
+  is switched off when the restore completes; after an error it stays on, and the message gives
+  the one line to switch it off and run the restore again. Maintenance mode that was on before
+  the restore stays on.
+- Adding a location whose repository config could not be read, while backup data is there,
+  no longer creates a new repository over it: it stops with an explanation. A snapshot that
+  cannot be taken over when a location is added is now logged instead of left out silently.
+- An SFTP connection that a Hetzner Storage Box dropped without phpseclib noticing is now
+  recognised and replaced: the check asks the server and counts its answer.
+- The extra connection a full restore reads ahead on is replaced when it breaks (up to 20 times),
+  instead of reading the rest of the restore the slow way.
+
+## [0.9.10] - 2026-10-19 (1.0.0-rc.4)
+
+Fourth release candidate for 1.0.0; the app version is 0.9.10. 1.0.0-rc.3 (0.9.9) was not
+released: its fixes are in here.
+
+### Changed
+- A full restore over SFTP reads the packs ahead on a connection of its own, 32 requests in
+  flight, into temporary files in the restore folder. From a Hetzner Storage Box to a server in
+  Canada (122 ms) packs now come in at about 14 MiB/s instead of 2.8. More connections can be set
+  with `restore_sftp_connections` (README). A part that cannot be read this way is read as
+  before. Restores from other locations work as before.
+- App store description: the line about Ensembia.
+
+### Fixed
+- After a full restore stopped halfway, running it again with `--force` was refused when the
+  database was already restored: Nextcloud then first wants `occ upgrade`. The guide and the
+  error message now say so.
+- A full restore of a backup made before 1.0.0-rc.2 with `--skip-missing-tables` failed on
+  PostgreSQL with "relation ... does not exist": the left-out tables were still looked up to set
+  their ID counters. It now skips them. A new test restores a backup made by 1.0.0-rc.1 on
+  PostgreSQL and MariaDB.
+- The app store showed old screenshots: it keeps a copy per URL, and the URLs always pointed at
+  `main`. They now point at the release's tag.
+
+## [0.9.8] - 2026-10-18 (1.0.0-rc.2)
+
+Second release candidate for 1.0.0; the app version is 0.9.8. Fixes from a full disaster recovery
+test of a production instance (about 1 TB, Nextcloud All-in-One onto a plain Nextcloud with
+PostgreSQL).
+
+### Added
+- `docs/DISASTER-RECOVERY.md`: step-by-step guide for when your server is gone.
+- `occ backup:restore:full --install-apps` installs (from the app store) or enables the apps the
+  old server had enabled, before the restore starts.
+
+### Changed
+- Backups record the structure of every database table. A full restore creates tables that do not
+  exist on the new instance, for example those left behind by an app that was removed long ago or
+  is switched off, instead of stopping at the first one.
+- A full restore no longer refuses when apps are missing: it restores their data and lists the
+  apps to install afterwards. `nextcloud-aio` is never required, so a backup of Nextcloud
+  All-in-One can be restored onto a plain Nextcloud.
+- A full restore onto an installation with a different table prefix (`dbtableprefix`) is refused
+  before it starts, with what to change, instead of restoring into tables nobody uses.
+- All problems are listed at once, with the app each missing table probably belongs to. For
+  backups made before this version, `--skip-missing-tables` leaves out tables whose structure is
+  unknown.
+- A fuller app store description, ready for 1.0.0, and a note on paid restore help by Ensembia.
+- README: switching the server to TCP BBR made backups over a long distance about 3 times faster.
+
+### Fixed
+- A full restore failed on foreign keys (for example those of the Mail app), because tables are
+  restored in name order. Foreign keys are now checked after all rows are loaded, before the
+  restore commits.
+- `occ backup:target:add` without a key pointed to `backup:key:init`, which makes a new key that
+  cannot read existing backups. It now points to `backup:key:import` for a restore, and says that
+  connecting to a location with backups can take a while. While it reads the index of a location
+  with backups, it shows how far it is and about how long it still takes.
+- A restore stopped with "Not found: packs/..." when the location was cleaned up while it ran,
+  for example by the weekly cleanup of the original server during a recovery test on a second
+  server: blobs that were moved into new packs were still looked for in the old ones. A restore
+  now reloads the index and reads them from where they are now.
+- Removing a location left its cached index in the database (tens of thousands of rows for a large
+  backup). It is removed with the location now, and once for locations that are already gone.
+
+## [0.9.7] - 2026-10-17 (1.0.0-rc.1)
+
+Release candidate for 1.0.0; the app version is 0.9.7. Only bug fixes until 1.0.0. Tested on a
+production instance (about 1 TB, 150,000 files): full and incremental backups and a verify on
+SFTP and SMB (Hetzner Storage Box) and S3 (OVH), a deep verify on SFTP, and partial restores from
+SMB and S3 checked against checksums.
+
+### Added
+- The admin page asks for feedback, with a link to a short "Experience report" form on GitHub:
+  which location, setup and size you used, and how it went.
+
+### Changed
+- New passphrases must be at least 16 characters (was 12). The location stores the key
+  encrypted with each passphrase, so the passphrase is what really protects the backups.
+  Existing passphrases keep working. The README and the how-to now say so, and why the
+  recovery kit must still be kept off the server.
+- Dates and times in the web interface follow the locale in the user's Nextcloud settings instead
+  of the browser's language, so a 24-hour locale shows 16:00 rather than 4:00 PM.
+- The list of backup runs (web interface and `occ backup:status`) shows the runs of the last 7
+  days, those still running, and at least the 5 newest; a failed run stays visible for that week.
+  `occ backup:status --all` and "Show older runs" in the web interface list all of them.
+- `occ backup:status` and `occ backup:verify` show durations of a day or more with the days
+  ("1d 12:10:13" instead of "12:10:13").
+
+### Fixed
+- With system cron, a running backup moved forward only every other cron run: Nextcloud
+  skipped the background job when cron came a few seconds before its 5-minute interval was
+  over, so a backup was idle 6 of every 10 minutes. The job now runs at every cron run.
+- Photos, video and other compressed data are no longer deflated only to throw the result away:
+  a quick test on three small slices of each block skips it. Compressing was the slowest part of
+  a backup (about 24 MiB/s).
+- Checking a backup on an S3 location (`occ backup:verify`) took hours on a large repository:
+  the index files were downloaded one at a time, at about two a second. They are now downloaded
+  16 at a time: on a production instance (27,585 index files, 1 TB) the check went from about
+  4 hours to 3.5 minutes.
+- Writing the snapshot at the end of a long backup to S3 took a quarter of an hour without any
+  progress shown: it read back the file list of every step one at a time. These reads are now
+  done 16 at a time on S3 (96 reads: 82 seconds before, 2 now), blobs that follow each other in
+  a pack are read at once on every location, the snapshot is written in a step of its own, and
+  the run shows "commit" while it does so.
+
+## [0.9.6-beta.7] - 2026-10-14
+
+Bugfix release for SMB locations, with `occ backup:cancel` to stop a backup that does not get
+anywhere. Tested on a production instance: a first full backup of 151,021 files (807 GiB) to OVH
+S3 completed, and a backup to a Hetzner Storage Box over SMB that had slowed to 12 GiB in 35
+hours ran at about 5.6 MiB/s after the update, while the S3 backup was still reading.
+
+### Added
+- The list of backup runs (web interface and `occ backup:status`) shows the total size of each
+  backup next to what it uploaded: an incremental backup of 1 TB that uploads 800 MB now shows
+  both. `occ backup:status` shows sizes in GiB where that reads better than MiB.
+- `occ backup:cancel <run>` stops a running backup; `occ backup:status` shows the run numbers.
+  No new step of the run starts, the step in progress finishes (usually within a minute), then
+  the process working on the run (`occ backup:run` or cron) stops. What it already stored is
+  removed by the next cleanup. A backup started by an earlier version is stopped as well: after
+  two minutes it is marked cancelled while it works, and its process stops at the end of the
+  step.
+
+### Fixed
+- Backups to SMB locations, and to other slow locations with many packs, slowed to a crawl: each
+  30-second step opened the location again, and reading the list of index files took longer
+  than the step itself. Each step then stored a single 4 MiB pack, which made the list longer
+  still. A first full backup of 0.8 TB to a Hetzner Storage Box over SMB managed 12 GiB in 35
+  hours. `occ backup:run` and system cron now open the location once per run, opening no longer
+  counts towards the step's time, and SMB folders are listed in one request instead of one per
+  file. A backup to an SMB location that is not getting anywhere keeps running in its old
+  process after the update: update first, then stop it with `occ backup:cancel <run>` and start
+  it again. The new backup reuses the packs the old one stored.
+
+## [0.9.5-beta.6] - 2026-10-12
+
+Bugfix release for SFTP locations and large repositories. Tested on a production instance with a
+1 TB repository on a Hetzner Storage Box over SFTP: a check in 5.5 minutes, a deep check of all
+316,529 blobs (815 GiB) in 11 hours, and an incremental backup in under 8 minutes.
+
+### Added
+- Progress of a running backup in the web interface and `occ backup:status`, e.g.
+  "running (files) 68%". The total is the size of the previous snapshot; for a first backup it
+  is estimated from Nextcloud's file cache (users' files, versions and trash) and shown as
+  "~68%".
+- Edit a backup location (web interface and `occ backup:target:edit`): change the password, host,
+  folder, connection type or name without losing its history. Before this the only option was a
+  new location, which starts an empty repository and, with a retention lock at the provider,
+  keeps paying for the old one. The new settings are only saved when they lead to the same
+  repository; stored passwords are never sent to the browser, and an empty password field keeps
+  the stored one. Administrators are notified of the change.
+- `occ backup:verify` reports how far it is every 30 seconds, and `occ backup:status` shows the
+  progress of a running check and how the last check of each location ended. On a large
+  repository a check takes hours, a deep one days.
+
+### Changed
+- Checking and opening a large repository over SFTP is much faster: the index files (one per
+  pack, 27,547 for 1 TB) are downloaded 32 at a time instead of one after the other, 114 instead
+  of 6 files per second to a Hetzner Storage Box (about 4 minutes instead of 77 for 1 TB). A check
+  of a repository with more than 256 packs also lists the pack folders (256 requests) instead of
+  asking for every pack.
+- App store listing: the author's e-mail address is shown.
+- App store listing: the homepage link points to the GitHub repository instead of back to the
+  app store page itself.
+- The notification for a location without a successful backup read "No successful backup to …
+  since never" when there had never been one; it now reads "No successful backup to … yet".
+
+### Fixed
+- 0.9.4 could not open a repository at the root of an SFTP location (empty path): its faster
+  SFTP reads sent their first request before phpseclib had opened the SFTP channel, which only
+  happens on the first SFTP call after login. Every backup then failed with "No repository at
+  this location". The channel is now opened first.
+- A check (`occ backup:verify`) did not renew its hold on the location while it downloaded the
+  index; on a large repository that takes longer than the hold lasts, so a weekly cleanup could
+  have started during the check.
+- A long first backup could end as failed although its snapshot was complete: when its final
+  step took longer than the step's lease (150 s with `occ backup:run`), the background job took
+  the run over, finished it a second time and failed on the snapshot it had already recorded,
+  overwriting the result. The lease now lasts at least 15 minutes, a step writes the run only if
+  no other process wrote it since the step loaded it (in one database statement), and recording
+  a snapshot that is already recorded is no longer an error.
+- `occ backup:verify` on a large repository failed with "SFTP connection failed while opening
+  snapshots/…" or "Not found: snapshots/…". A Hetzner Storage Box drops an SFTP connection that
+  carried a lot of data (some 40 MB) and then stayed quiet for a few minutes, and the check went
+  quiet after downloading the index: it refreshed the local index cache, first in 29 minutes (a
+  pass over all blobs for every pack: 27,547 packs, 400,000 blobs for 1 TB), then still in more
+  than 6 minutes (a database transaction per pack on PostgreSQL). Nextcloud's SFTP storage keeps
+  using a dropped connection, on which every file looks missing. Now:
+  - an SFTP connection that was not used for a minute is checked first, and one that turns out
+    to be dead after a failed request is replaced, once per request; uploads, moves and deletes
+    are only checked first, never repeated;
+  - the index cache is written in one transaction (27,547 packs in 11 seconds on a test server,
+    against about a minute row by row);
+  - after a check the cache holds the index files as they are: before, a blob that was in two
+    packs was only cached for one of them.
+
+## [0.9.4-beta.5] - 2026-10-09
+
+Bugfix release: faster restores.
+
+### Fixed
+- Restores and `occ backup:verify --deep` fetched every blob with its own request, so on a
+  remote location they ran far below the speed of the connection. The blobs of a pack are now
+  read from one open stream, in the order they were written. Restoring 86 MB in 202 files from a
+  Hetzner Storage Box over SMB went from 0.78 MB/s to 4.2 MB/s, the speed of reading the packs
+  as plain files over that connection.
+- Reading from an SFTP location waited a full round trip for every 256 KiB, whatever the line
+  speed. Reads now keep up to 8 requests in flight. Restoring 1.97 GB in 500 files from a Hetzner
+  Storage Box (47 ms away) took 694 s before the fix above, 499 s with it and 142 s with both
+  (2.8 → 3.9 → 13.9 MB/s); a full 51 GB restore ran at 13.0 MB/s. When a server error
+  interrupts such a read, it goes on from the same position with Nextcloud's own SFTP stream;
+  after three failing files in a row, or on a Nextcloud whose SFTP library lacks what this needs,
+  only Nextcloud's own stream is used.
+- README: a WebDAV location on a slow upload needs a higher `davstorage.request_timeout`.
+
+## [0.9.3-beta.4] - 2026-10-08
+
+Bugfix release.
+
+### Fixed
+- A backup failed with "cannot execute INSERT in a read-only transaction" on PostgreSQL as soon
+  as the database dump filled a whole pack (32 MiB): the pack's index cache row was written
+  inside the read-only dump transaction. On other databases that row was rolled back silently.
+- Backups to a remote location slowed down as the repository grew: every backup step listed the
+  repository's index with a round trip per file. Over SFTP to a Hetzner Storage Box a 60 GiB
+  repository already lost a large part of each step to it; backing up continuously
+  (`occ backup:run`) went from 45 KiB/s to 5.8 MB/s with the fix.
+
+## [0.9.2-beta.3] - 2026-10-08
+
+Bugfix release.
+
+### Added
+- README: notes on using a Hetzner Storage Box over WebDAV and SMB.
+
+### Fixed
+- Adding a backup location in the web interface failed with "Request failed with status code 403"
+  when the login was more than 30 minutes old: the form did not ask for password confirmation.
+- Settings page: the "Backup and restore" / "Settings" tabs line up with the sections below them.
+- Backups: the runs table scrolls horizontally on narrow screens instead of running off the page.
+- `occ backup:verify --deep`: a blob that could not be read (network or storage error) was reported
+  as "corrupted or tampered". Reads are now retried, and a read that keeps failing is reported
+  separately as unreadable, with the error (run the check again; if the same blobs stay unreadable,
+  their pack may be damaged or truncated). Only a blob that was read but fails decryption or its
+  hash check counts as corrupted. Found on a Hetzner Storage Box over WebDAV, where the blob
+  turned out to be intact.
+
+## [0.9.1-beta.2] - 2026-10-07
+
+Second beta, the first release in the Nextcloud app store (signed).
+
+### Added
+- App store listing: screenshots, website, repository and documentation link in `appinfo/info.xml`.
+
+### Fixed
+- Restore: the "new folder" option showed `"Restored "` without the date pattern.
+- Restore: the restore-point dropdown cut off the time.
+- Settings: the passphrase actions are on one line instead of stacked.
+- `docs/HOWTO.md`: the SFTP example used a non-existent auth mechanism (`sftp::password`
+  instead of `password::password`).
+
+## [0.9.0-beta.1] - 2026-10-07
+
+First beta. Tested thoroughly and usable **alongside** your current backup, but **not yet a
+drop-in replacement** for it. We test what we can ourselves (Nextcloud 32–35, SQLite, MariaDB and
+PostgreSQL, S3, SFTP, FTP, SMB and NFS), but we need field experience from other setups: please
+report what works and what doesn't, especially on large instances and on storage providers not
+listed in the README.
+
+### Added
+- Disaster recovery: `occ backup:key:import` and `occ backup:restore:full` restore the database,
+  data directory and config onto a fresh installation of the same major version.
+- Per-user backup and restore via user_migration: `occ backup:user:backup` and
+  `occ backup:user:restore` (replace the account after a safety export, or restore as
+  `<uid>-bak`), also onto a server where the user does not exist yet. The commands ask before
+  installing user_migration (or take `--install-user-migration`).
+- Checksum audit: `occ backup:verify`, shallow or `--deep`, for snapshots and per-user exports.
+- Retention for per-user exports: `occ backup:retention --user-last=N`.
+- FTP and SMB covered by the integration tests; NFS through the `local` backend on a mounted share.
+- `docs/HOWTO.md`: step by step from setup to a tested restore.
+- Warnings when a backup finishes with unreadable files or folders, or with files that kept
+  changing while being read (log, `occ`, notification, snapshot).
+
+### Changed
+- `backup:restore:full` refuses on an installation with more than one user and asks first;
+  `backup:user:restore --mode=replace` asks before deleting an existing account (`--force` for
+  scripts in both cases).
+- A failed scheduled backup is retried at most three times a day, an hour apart.
+- The recovery kit carries the deletion delay; the kit file is created owner-only.
+- Adding a location through the web API needs password confirmation.
+
+### Fixed
+- Exports of users whose id contains `.part-` could be deleted by cleanup on remote locations.
+- Cleanup no longer frees the data of a per-user export whose manifest is missing.
+- Crash safety of moving snapshots to and from the trash, of catalog writes by concurrent
+  backups and per-user exports, and of short uploads.
+- A file that keeps changing no longer makes a backup restart forever.
+- Long restores and exports keep their lock on the location alive.
+- Floating-point database columns are dumped exactly.
+
+### Known limitations
+See "Known limitations" in the README: memory use on very large instances, never two servers
+writing to one location, removing a passphrase slot does not revoke access, no rollback detection
+before a disaster recovery, and a few smaller points. None of them block the road to 1.0.0; they
+are on the backlog in `PLAN.md`.
 
 ## [0.1.0-alpha.1] - 2026-10-05
 
@@ -42,3 +518,19 @@ and not implemented yet.
 - No FTP/SMB coverage in CI yet, and no verification/checksum-audit command yet (phase 2).
 - See the "Storage backend experiences" section of the README for provider-specific quirks found
   so far (e.g. Hetzner Storage Box sub-accounts).
+
+[1.0.1]: https://github.com/dillardblom/ng_backup/releases/tag/v1.0.1
+[1.0.0]: https://github.com/dillardblom/ng_backup/releases/tag/v1.0.0
+[0.9.12]: https://github.com/dillardblom/ng_backup/releases/tag/v1.0.0-rc.6
+[0.9.11]: https://github.com/dillardblom/ng_backup/releases/tag/v1.0.0-rc.5
+[0.9.10]: https://github.com/dillardblom/ng_backup/releases/tag/v1.0.0-rc.4
+[0.9.8]: https://github.com/dillardblom/ng_backup/releases/tag/v1.0.0-rc.2
+[0.9.7]: https://github.com/dillardblom/ng_backup/releases/tag/v1.0.0-rc.1
+[0.9.6-beta.7]: https://github.com/dillardblom/ng_backup/releases/tag/v0.9.6-beta.7
+[0.9.5-beta.6]: https://github.com/dillardblom/ng_backup/releases/tag/v0.9.5-beta.6
+[0.9.4-beta.5]: https://github.com/dillardblom/ng_backup/releases/tag/v0.9.4-beta.5
+[0.9.3-beta.4]: https://github.com/dillardblom/ng_backup/releases/tag/v0.9.3-beta.4
+[0.9.2-beta.3]: https://github.com/dillardblom/ng_backup/releases/tag/v0.9.2-beta.3
+[0.9.1-beta.2]: https://github.com/dillardblom/ng_backup/releases/tag/v0.9.1-beta.2
+[0.9.0-beta.1]: https://github.com/dillardblom/ng_backup/releases/tag/v0.9.0-beta.1
+[0.1.0-alpha.1]: https://github.com/dillardblom/ng_backup/releases/tag/v0.1.0-alpha.1

PLAN.md

@@ -276,7 +276,7 @@ onderdelen wel en niet terugkomen, op basis van de geregistreerde migrators.
 | `backup:list [--target=]` | herstelpunten |
 | `backup:verify <snapshot> [--deep]` | checksums controleren, optioneel alles ontsleutelen |
 | `backup:restore:file <snapshot> <user> <pad> [--to=]` | bestand/map terugzetten |
-| `backup:restore:user <snapshot> <user> [--to-user=]` | gebruiker terugzetten via user_migration (fase 2) |
+| `backup:user:restore <snapshot> <user> [--to-user=]` | gebruiker terugzetten via user_migration (fase 2) |
 | `backup:restore:full <snapshot>` | volledige restore (fase 2, verse installatie) |
 | `backup:target:add/list/remove/test` | opslagdoelen beheren en testen |
 | `backup:key:export / import` | herstelkit |
@@ -338,6 +338,305 @@ een backup-app die niet betrouwbaar is, is erger dan geen backup-app.
 Volgorde: fase 1 grondig testen, reviewen en debuggen; dan nadenken over 0.1.0-alpha.1. Een
 minimale volledige restore (`occ backup:restore:full` op een verse installatie) komt vóór de beta.
 
+**Roadmap-indeling fase 2 (besluit 2026-10-05):** naar v1.2.0 toewerken met in fase 2:
+1. `backup:restore:full` (disaster recovery, verse installatie) — **klaar** (2026-10-05)
+2. FTP/SMB-ondersteuning — **klaar** (2026-10-06): beide liepen al via files_external's generieke
+   adapter zonder enige ng_backup-code; alleen testdekking toegevoegd
+   (`tests/integration/targets-matrix.sh`) + bevindingen in README ("Storage backend experiences").
+   SMB vereist de `smbclient` PECL-extensie (niet standaard in de Nextcloud-image, in CI nu
+   on-the-fly gebouwd). NFS is geen eigen backend: lokaal mounten + `local`-backend erop richten.
+3. Verificatie/checksum-audit-commando — **klaar** (2026-10-05)
+4. Retentie/prune voor user-exports — **klaar** (2026-10-06): `occ backup:retention --user-last=N`
+   (standaard 3, per installatie, net als de bestaande snapshot-policy), toegepast door
+   `occ backup:prune` (geen prullenbak voor user-exports, in tegenstelling tot snapshots — on-demand,
+   niet het primaire vangnet).
+5. Automatische user-export in het reguliere schema — **naar backlog** (niet voor deze release; on-demand blijft)
+9. SMB-roundtrip (protocol, niet een specifieke server) — **klaar** (2026-10-06): CI-matrix, 2 GB-roundtrip en
+   user-export via SMB; NFS via de OMV-share getest (`local`-backend op een gemounte share, 2026-10-06)
+10. `backup:user:restore` zonder user_migration: vraagt om toestemming om de app te installeren en te activeren (of
+   `--install-user-migration`) — **klaar** (2026-10-06); waarschuwing over de settings-allowlist — **klaar**;
+   agenda/contacten bij migratie naar een server zonder die gebruiker — **getest** (2026-10-06, naar `migrated-personal`/`migrated-contacts`)
+    Backlog: (a) de originele weergavenaam herstellen (het label uit de export is niet getest als
+    weergavenaam); (b) de interne `migrated-`-naam hernoemen (vereist directe databasewijziging, niet voor de beta).
+
+**Backlog uit de pre-beta review (2026-10-07)** — geen belemmering voor 0.9.0-beta of 1.0.0, staat
+in README "Known limitations":
+1. Geheugen bij grote instanties (>1 TB, miljoenen bestanden): blob-index, prune-set, browse van een
+   snapshot in de web-UI, `trashExtras` bij restore en het manifest van een user-export staan volledig
+   in het geheugen; streaming/paginering nodig.
+2. Twee servers op één locatie: catalogus kan breken (generatie overschreven, of anchor >200 generaties
+   achter). Docs-waarschuwing staat er; mogelijk later een echte put-if-absent per backend.
+3. Sleutelrotatie: een slot verwijderen trekt geen toegang in (master-key blijft gelijk).
+4. Rollback vóór DR niet detecteerbaar: referentie-generatie en -hash in de kit opnemen of tonen.
+5. Kit-velden buiten `wrapped_key` (o.a. `delete_delay_days`) zijn niet geauthenticeerd; nu alleen getoond.
+6. Repository-id in de AD van objecten (formaatwijziging).
+7. Wachtwoorden van locaties via `--option-file` of omgevingsvariabele i.p.v. de commandoregel.
+8. Tijdelijke restore-bestanden niet via de Files-API verwijderen (komen nu in de prullenbak).
+9. DB-restore in foreign-key-volgorde (cascades).
+10. Packs zonder index (index-upload mislukt) opruimen.
+11. `backup:restore:full` in onderhoudsmodus en hervatbaar maken; nu: opnieuw draaien met `--force`.
+12. Config/rename op FTP/SMB-servers die geen rename over een bestaand bestand toestaan.
+
+**Plan richting 1.0.0 en 1.1.0 (besluit 2026-10-15/16):**
+- **1.0.0-rc.1:** wat nu op `polish` staat (snelle S3-verify en snapshot-commit, kortere runlijst,
+  duur met dagen, job bij elke cron-run, deflate-test, feedbackformulier, datums in de locale van
+  de gebruiker, wachtwoordzin min. 16 tekens). Geen nieuwe functies meer.
+- **Vóór 1.0.0 (verplicht):** volledige restore met kit op een tweede server (PVE02), alleen lezend
+  of op een kopie van de locatie; plus een user-restore. Zonder geslaagde test geen 1.0.0.
+- **1.0.0 (besluit 2026-10-18):** alleen betrouwbaarheid. rc2 uitgebracht; slaagt de grote
+  DR-test op VM 980 (snapshot van 12-10, met `--skip-missing-tables`), dan 1.0.0. Zo niet: fix,
+  rc3, en rc3 pas uitbrengen na een geslaagde volledige DR-test.
+- **rc4 (besluit 2026-10-19):** rc3 is niet uitgebracht. De DR-test met rc3 liep ~2,8 MiB/s
+  (~3,5 dag); parallel lezen over SFTP haalde vanaf VM 980 ~7,6 MiB/s. Daarom rc4 = rc3 +
+  vooruitlezen over SFTP (4 eigen verbindingen). Volgorde: volledige DR-test op VM 980 volgens de
+  gids (SFTP, Storage Box) → rc4 uitbrengen en om tests vragen → zelf een volledige DR van een
+  productie-instantie van ~250 GB via S3 en via SMB. Drie volledige DR-restores vóór 1.0.0.
+  Problemen of meldingen van gebruikers: rc5.
+- **1.0.2** (plan akkoord 2026-11-04): punten 1, 2 en 5 hieronder, de Bin, nieuwe screenshots en
+  het polish-punt over de schatting van `target:add`. Besluiten 2026-11-04:
+  - `--salvage` haalt ook bij een kapotte database terug wat kan: bestanden zijn per gebruiker
+    gescheiden en het waardevolst. Kan de database niet terug (dump onleesbaar, of past niet op
+    deze installatie), dan blijft de verse database staan en gaan data en config van de backup
+    naar `<datadir>/ngb-salvage-<snapshot>/`; vanaf daar is het handwerk. Exitcode 2.
+  - De DR-test met een backup mét tabelstructuur, zonder `--skip-missing-tables` (punt 3), is
+    nog niet gedaan en wordt ingepland vóór de release van 1.0.2. Ingepland (2026-11-04): een
+    verse snapshot van nc01 (gemaakt met 1.0.1, dus met tabelstructuur) volgens de DR-gids
+    terugzetten op VM 980 met de 1.0.2-build, over **SMB** (Storage Box; besluit 2026-11-04:
+    SMB in plaats van SFTP, zodat de DR-test de nieuwe SMB-leescode op echte schaal en over de
+    echte lijn vanuit Canada test; vorige meting 2,6 MiB/s, verwachting ~1 dag voor 1 TB), zonder
+    `--skip-missing-tables`; daarna `--salvage` op een deel van de bestanden (moet hetzelfde
+    resultaat geven, exitcode 0). Uitvoeren met Dillard, die VM 980 klaarzet; deze week, vóór
+    de release. Screenshots akkoord (2026-11-04).
+  **DR-test 1.0.2 over SMB (VM 980, snapshot a86271ed van nc01, 983 GiB, gestart 2026-11-04):**
+  index lezen 8 uur (~1 bestand/s; daarna versneld naar 0,66 s/bestand, gemeten vanaf VM 980);
+  restore zonder opties (geen `--install-apps`, geen `--skip-missing-tables`) liep ~12 MiB/s
+  (SFTP eerder 2,8-7,6; SMB vóór 1.0.2 2,6). Na 392 GiB viel de SMB-verbinding weg en bleef de
+  restore op 100% CPU hangen: de smbclient-extensie geeft bij een mislukte read een string met
+  lengte -1. Opgelost (controle + nieuwe verbinding), plus hervatten: `--force` laat bestanden met
+  dezelfde grootte en mtime staan. Hervat 2026-11-05 07:21 UTC na `maintenance:mode --off`
+  volgens de gids; binnen 10 min voorbij de 392 GiB. SMB op sub5 na de test weer uitzetten.
+  **Resultaat (klaar 2026-11-06 02:11 UTC, nazorg 02:27):** hervatte run 18 u 50 min, exit 0, 150.755
+  bestanden; 7-13 MiB/s (langzamer vanaf ~18 uur Duitse tijd, oorzaak niet vastgesteld). Vergeleken
+  met nc01: 150.467 van 150.758 bestanden gelijk in grootte en mtime, 397 op hash zonder verschil;
+  gebruikers, agenda's, contacten, shares en Deck gelijk; bestanden, agenda en contacten via WebDAV
+  getest als gebruiker. `backup:restore --salvage` op 16.904 bestanden: exit 0, geen verschil. Niet
+  vastgesteld: de 50.080 "updated" bij `files:scan`. Zonder `--install-apps` 51 van de 81 apps aan.
+  VM's 980-982 en de sim-backups op OVH en sub6 opgeruimd.
+  **Naar 1.0.3 (besluit 2026-11-06):** lege mappen komen niet terug (3.982 op nc01, 2.076 daarvan in
+  `files`, verklaart vrijwel zeker de 2.370 "removed" bij `files:scan`). De backup legt alleen
+  bestanden vast (`walk()`), dus oudere snapshots hebben ze niet. Voor een DR acceptabel, wel
+  fixen; issue #27. Daarna kleine volledige simulaties; een DR van 1 TB is hiervoor niet nodig.
+  **Salvage vóór de release getest (besluit 2026-11-06):** nieuwe modus `salvage-files` in
+  `full-restore-roundtrip.sh`, ook in CI: één pack beschadigd en één weg. Eerst stopt de restore,
+  daarna `--salvage --force` volgens de gids. Vond één fout: bij een ontbrekend bestand wees de
+  melding niet naar `--salvage` (opgelost).
+  Stand 2026-11-04 (`polish`, gepusht): cron-waarschuwing + tick vanaf de pagina +
+  voortgang van de db-fase; `--salvage` voor `backup:restore` en `backup:restore:full`; S3
+  vooruitlezen (8 ranges tegelijk, met `SaveAs` naar de spool); SMB in leesacties van 8 MiB
+  (gemeten met netem, 130 ms RTT: 4,5 → 18 MiB/s per leesactie; een volledige restore over SMB
+  met vertraging is nog niet gemeten); Bin-tabblad; schatting `target:add`; nieuwe screenshots
+  (1–3 vervangen, 4-bin erbij; in `info.xml` bij de release naar tag v1.0.2 laten wijzen en
+  4-bin toevoegen). Getest: unit (208), psalm, integratie NC35 sqlite/pgsql, S3/SFTP/FTP/SMB,
+  volledige restore met `--salvage`. Nog te doen: DR-test, release.
+- **1.0.1** (uitgebracht 2026-11-01): alleen de kleine punten (besluit 2026-10-30): 4, 6–13. Punten 1, 2 en 5 gaan naar
+  1.0.2 (README-roadmap aangepast); punt 3 is een test, ingepland voor de week van 2 november,
+  niet aangekondigd en los van de release. Voor 1.0.2 ook: nieuwe screenshots (het labelveld bij
+  "Back up now" en het tabblad Docs staan er nog niet op; besluit 2026-11-01), en de prullenbak
+  van herstelpunten naar een eigen tabblad "Bin" naast "Backup and restore", "Settings" en "Docs":
+  onder de lijst met herstelpunten vervuilt hij het scherm (vooral met wat het bewaarbeleid erin
+  zet; besluit 2026-11-01). Nieuwe screenshots daarna, zodat de Bin er ook op staat.
+  1. **Naar 1.0.2.** (Naar rc4: herstelsnelheid over SFTP.) S3 leest al 16 tegelijk bij index en tree, maar een
+     restore leest de packs nog één voor één: ook vooruitlezen via de S3-client.
+  2. **Naar 1.0.2.** Achtergrondjobs zonder systeem-cron (issue #13; besluit 2026-10-19). De PR die dit
+     oplost zegt "Fixes #13" (bevestigd: #13 was de cron; besluit 2026-10-21):
+     a. **Waarschuwen** in de beheerpagina en `backup:status`: modus uit `core backgroundjobs_mode`
+        (`ajax`/`webcron`/`cron`) en de laatste run uit `core lastcron`. Niet op `cron`, of de
+        laatste run te lang geleden: melding met de cron-regel erbij ("Backups only move while
+        someone has Nextcloud open"), en "waiting for background jobs" als een lopende backup lang
+        geen stap zette.
+     b. **De pagina laat de backup lopen** zolang ze openstaat: in `ajax`/`webcron` voert de
+        statusaanroep die de pagina toch al herhaalt ook een korte, begrensde stap uit (zoals de
+        korte stappen die AJAX-cron nu al krijgt). "Back up now" werkt dan ook zonder cron zolang
+        het tabblad openstaat; de melding zegt dat geplande backups echte cron nodig hebben.
+        De melding zegt (zonder werkende systeem-cron): backups hebben systeem-cron nodig, ook de
+        gewone nachtelijke; zo stel je cron in (link naar de Nextcloud-documentatie over
+        achtergrondjobs voor de versie van de server, nu
+        https://docs.nextcloud.com/server/34/admin_manual/configuration_server/background_jobs_configuration.html,
+        versienummer uit de server, niet vast); zolang er geen cron is, loopt een backup die je
+        met de knop start alleen door terwijl de NG Backup-pagina openstaat.
+     c. **Voortgang in de databasefase** (issue #13): nu staat er alleen "running (db)", wat er
+        hetzelfde uitziet als vastzitten. Toon "running (db: 47/183 tables)" zoals de bestandsfase
+        een percentage toont, en "waiting for background jobs (last ran 12 min ago)" als een run
+        een tijd geen stap zette, ook bij een cron die is blijven staan.
+     Niet doen: de cron-modus vanuit de app omzetten (zonder echte cron-regel stopt alles, en
+     `cron.php` zet de modus zelf op `cron`), en geen `exec php occ backup:run &` vanuit de knop
+     (vaak uitgeschakeld, niet op hosted, buiten Nextcloud om lastig te volgen en te stoppen).
+  3. Volledige DR-test met een backup die al de tabelstructuur bevat (gemaakt met rc2 of later),
+     zonder `--skip-missing-tables`: dat pad is op 1 TB nog niet getest.
+  4. **Label bij "Back up now"** (besluit 2026-10-19): een optioneel tekstveld naast de knop; de
+     tekst gaat als label van de snapshot mee (nu kan dat alleen met `occ backup:run -l`; de knop
+     stuurt een leeg label, geplande runs krijgen "scheduled"). Raakt alleen de UI en een
+     bestaande parameter. Ten hoogste 100 tekens — **klaar** (2026-10-30).
+  5. **`--salvage`** voor `backup:restore` en `backup:restore:full` (besluit 2026-10-22): terughalen
+     wat kan, een bestand dat niet te lezen of te ontsleutelen is overslaan en aan het eind
+     opsommen, in plaats van stoppen. **Naar 1.0.2** (besluit 2026-10-30).
+  6. **Tijdelijke bestanden van een afgebroken restore opruimen** (gevonden in de SMB-DR van
+     rc6, 2026-10-24): de rc5-poging die stopte liet `VID_0009.mp4.ngb-restore-<id>` staan; de
+     geslaagde restore daarna haalde het niet weg, en `files:scan` maakte het zichtbaar in Files.
+     Een restore ruimt `*.ngb-restore-*` in de mappen die hij terugzet op (alleen bestanden met
+     precies dat achtervoegsel en 6 of 12 hextekens) — **klaar** (2026-10-30).
+  7. **Eén bestand terugzetten met `backup:restore`**: een pad naar een bestand zet 0 bestanden
+     terug (er komt een `/` achter); nu werkt alleen een map. Gold alleen voor `--to-directory`;
+     naar de bestanden van een gebruiker werkte een los bestand al — **klaar** (2026-10-30).
+  8. **Uitleg (i) bij de prullenbak van herstelpunten** (besluit 2026-10-25): bij "removed by
+     retention policy" een infoknop met wat het betekent: het bewaarbeleid houdt voor oudere dagen
+     één herstelpunt per dag (het laatste), weken en maanden; de rest gaat naar de prullenbak en
+     wordt pas na de ingestelde wachttijd (`delete_delay_days`, standaard 30) echt verwijderd, en is
+     tot die datum terug te zetten. Aanleiding: de beheerder zag "19-10 13:12 – after rc4 upgrade
+     removed by retention policy" en dacht dat er iets was weggegooid. `occ backup:trash` zegt
+     hetzelfde onder de lijst — **klaar** (2026-10-30).
+  9. **Tijdzone in `occ backup:status`**: de tabel toont de servertijd (UTC), de webinterface de
+     tijd van de beheerder; dat leest als een verkeerde starttijd. Zet de zone in de kolomkop
+     ("started (UTC)") of toon de tijden in de zone van het schema. Gedaan: beide, en ook in
+     `backup:list`, `backup:trash` en `backup:browse` — **klaar** (2026-10-30).
+  10. **User-restore op gebruikersnaam** (issue #22, 2026-10-27): `backup:user:restore <locatie>
+      New_User` gaf alleen "is not a recorded user export"; het argument moet het manifestpad
+      zijn, dat alleen `backup:user:backup` eenmalig toonde. Nu: `backup:user:list` toont de
+      exports, een kale uid werkt bij precies één export, anders een lijst om uit te kiezen —
+      **klaar** (2026-10-27).
+  11. **Tabblad "Docs" in de beheerpagina** (besluit 2026-10-27): een derde knop naast "Backup and
+      restore" en "Settings", met links naar de HOWTO (`docs/HOWTO.md`), de DR-gids
+      (`docs/DISASTER-RECOVERY.md`) en de roadmap (README, `#roadmap`) op GitHub, elk met een
+      regel wat erin staat. Nu zijn ze alleen via de README te vinden. Zichtbaar ook zonder
+      sleutel, zodat de gids vindbaar is vóór de eerste installatie-stap. "NG Backup is in beta"
+      gaat uit de feedbackregel — **klaar** (2026-10-27).
+  12. **SFTP-sleutel zonder regeleinden** (issue #24, 2026-10-28): het veld "Private key" op de
+      beheerpagina is één regel, dus een geplakte sleutel verliest zijn regeleinden. NC34
+      (phpseclib 2) las dat nog, NC35 (phpseclib 3) weigert een OpenSSH-sleutel dan met "Unable
+      to read key". De regeleinden worden nu teruggezet vlak voor gebruik — **klaar** (2026-10-28).
+  13. **"database is locked" bij het begin van `backup:restore:full` op SQLite** (CI, 2026-10-26
+      bij #22 en 2026-10-29 op `main` na de merge van 1.0.0): de restore stopt meteen na het
+      aanzetten van de onderhoudsmodus. Niet altijd, dus een tweede proces dat op hetzelfde moment
+      de database gebruikt (cron, een webverzoek of de opstart van de container). Kan ook bij een
+      echte restore naar SQLite gebeuren. Oorzaak (2026-10-29): SQLite (WAL) begint een transactie
+      als lezer; schrijft een ander proces tussen ons eerste lezen en ons eerste schrijven, dan
+      faalt dat schrijven direct (geen wachttijd helpt). In CI was dat de installer, die
+      "installed" zet en daarna nog seconden doorschrijft. Nu neemt de restore eerst het
+      schrijfslot en wacht hij op de ander; de SQLite-test draait met een tweede schrijver
+      ernaast — **klaar** (2026-10-29).
+- **DR-tests over databasegrenzen** (besluit 2026-10-20; productie nc01 draait PostgreSQL): na
+  de MariaDB→PostgreSQL-fout (tellers, rc5) elke overstap in de integratietest (`to-pgsql`,
+  `to-mysql`, `to-sqlite`, ook in CI). Volle DR-tests met echte data: vóór 1.0.0 de S3-simulatie
+  (MariaDB-bron, 138 GB) nogmaals naar een MariaDB-doel en de SMB-simulatie naar een SQLite-doel;
+  **na 1.0.0** de 1 TB van nc01 (PostgreSQL) naar een MariaDB-doel.
+- **Polish:** `target:add` toonde bij het eerste indexbestand al "about 642 min left" (S3,
+  4.568 bestanden, daarna binnen een minuut klaar): een schatting pas na ~5% of na meer dan
+  een paar bestanden.
+- **1.1.0:**
+  1. `backup:key:import` zonder kit: de sleutel-slots van de locatie (`config`) lezen, met de kit
+     als reserve als `config` ontbreekt of niet opent. Vergt een andere volgorde van
+     `target:add` en sleutelimport (het gevoeligste pad), daarom niet in rc1. Daarna de
+     DR-test op PVE02 herhalen zonder kit.
+  2. Instelling "zware achtergrondjobs pauzeren tijdens een backup" (standaard aan, uit te zetten):
+     Memories, files_antivirus BackgroundScanner, Recognize, Preview Generator, fulltextsearch.
+     Via de reservering/last_run van die jobs (geen apps uitzetten), crashbestendig, maximaal
+     ~6 uur achter elkaar, zichtbaar in UI en log. Op nc01 met de hand getest tijdens SMB-run 10.
+  3. Snelheid: lezen en uploaden laten overlappen, meerdere bestanden tegelijk lezen, eventueel
+     een eigen worker (`occ background-job:worker`). Gemeten op nc01: 55% wachten op de schijf,
+     33% op de SMB-upload, ~7% CPU. Vergt extra PHP-processen; botst mogelijk met uitgangspunt 1.
+  4. **Schema per locatie** (besluit 2026-10-19): in de instellingen van een locatie "uit",
+     "dagelijks om HH:MM" of "elke N uur (vanaf HH:MM)". Nu is er één `schedule_time` voor alle
+     locaties, één keer per dag. Bij de update wordt de huidige tijd het schema van elke
+     bestaande locatie (voor bestaande gebruikers verandert er niets).
+  5. **Locaties na elkaar laten starten** in plaats van tegelijk: twee runs die dezelfde schijven
+     lezen zijn samen niet sneller (gezien op nc01); wachtende runs zichtbaar als "queued".
+  7. **SMB sneller** (gemeten 2026-10-21): lokaal netwerk zonder vertraging (Samba-container op de
+     laptop, 1,8 GB) back-up 24,9 MB/s, restore 27,6 MiB/s; vanaf Canada naar de Storage Box (130 ms)
+     2,6 MiB/s, omdat SMB per blok op het antwoord wacht. Grotere schrijfblokken, en vooruitlezen
+     bij een restore zoals SFTP (IReadsAhead) of meerdere packs tegelijk. Een NAS met 1 Gbit haalt
+     ~110 MB/s: daar is winst.
+     Ook de index: `target:add` over SMB vanaf Canada haalt ~1 indexbestand per seconde (4.927
+     bestanden ~85 min), want SMB krijgt geen `getMany()` met verzoeken tegelijk zoals S3 en SFTP.
+  6. **Notitie achteraf bij een restorepunt**, te wijzigen in de lijst. Het label in de snapshot
+     is versleuteld en ligt vast; de notitie apart op de locatie bewaren (bijv. in de catalogus),
+     zodat een nieuwe server na een DR hem ook ziet.
+  8. **Herstelpunt vastpinnen** (besluit 2026-10-25): een herstelpunt dat het bewaarbeleid
+     nooit opruimt (bijv. "vóór de upgrade naar NC 35"), in de lijst en met
+     `occ backup:pin <snapshot>` / `--unpin`. Op de locatie bewaren (catalogus), zodat de
+     opschoning het ziet, ook na een DR; vastgepinde punten tellen niet mee in last/daily/weekly.
+  9. **Feedbackvraag weghalen** in 1.1.0 of 1.2.0 (besluit 2026-10-27): de regel "We would like
+     to hear how NG Backup works for you ... Share your experience" in de beheerpagina blijft tot
+     dan staan (de vermelding "in beta" is er in 1.0.1 al af). Zijn er tegen die
+     tijd geen noemenswaardige meldingen, dan werkt het: mensen melden eerder wat niet werkt dan
+     wat gewoon werkt. Het formulier (`experience.yml`) mag blijven voor wie het zelf opzoekt.
+- **Bevindingen DR-test op PVE02 (2026-10-17, snapshot van nc01, 1 TB, AIO → gewone NC 34 met
+  PostgreSQL 18)** — voor **1.0.0-rc.2**:
+  1. Tabellen van apps die bij de backup **niet aanstonden** (restanten: Deck, ONLYOFFICE,
+     AppAPI, een archief-app) blokkeren de restore met één tabelnaam per poging. Standaard
+     overslaan met één waarschuwing per app; optie om ze toch terug te zetten.
+  2. Alle ontbrekende apps en tabellen **vooraf in één lijst**, per app benoemd (nu één per poging,
+     ook voor uitgeschakelde standaard-apps zoals `admin_audit`).
+  3. `--skip-missing-apps`; `nextcloud-aio` standaard overslaan (bestaat buiten AIO niet), zodat
+     AIO → gewone Nextcloud werkt.
+  4. `--install-apps`: ontbrekende apps uit de app store installeren.
+  5. Apps buiten de app store (eigen builds, `side_menu`, `nextcloud-aio`): documenteren; later
+     eventueel `custom_apps` meenemen in de backup.
+  6. Tabellen van een app die wél aanstond maar die hun tabel later zelf maakt (Memories:
+     `memories_planet_geometry`) netjes afhandelen.
+  7. `backup:target:add` zonder sleutel verwijst naar `key:init`; als er al een repository staat,
+     moet het naar `key:import <kit>` wijzen.
+  8. `backup:target:add` toont geen voortgang bij het ophalen van de index (27.582 bestanden).
+  9. `backup:target:remove` laat de index-cache van die locatie in de database staan; opruimen,
+     ook bestaande wezen.
+  10. Snapshot-meta uitbreiden: ook geïnstalleerde maar uitgeschakelde apps, met per app of hij
+      uit de app store komt; `occ backup:apps <locatie> <snapshot>` toont de lijst leesbaar
+      (geen platte tekst op de locatie: dat lekt welke apps/versies er draaien).
+  11. **Tabelstructuur meedumpen** (kolommen, typen, indexen, primary key), zodat de restore een
+      ontbrekende tabel zelf aanmaakt met de gegevens erin. Lost restanten van oude apps op zonder
+      ze over te slaan; een later opnieuw geïnstalleerde app vindt zijn oude gegevens terug.
+  12. **Foreign keys**: de restore zet tabellen op alfabet terug; `oc_mail_accounts` verwijst naar
+      `oc_mail_mailboxes` en PostgreSQL weigert (fk_61a7e87f59a77cdc). Iedereen met Mail loopt hier
+      vast. Oplossing: in de juiste volgorde terugzetten (afhankelijkheden eerst), of de controle
+      tijdelijk uitzetten en na afloop terugzetten en controleren. In de test: 15 FK's (alle van
+      Mail) tijdelijk verwijderd en na de restore teruggezet: alle 15 geldig op de teruggezette
+      data, dus "uitzetten, terugzetten, achteraf controleren" werkt.
+  13. **SFTP-restore over een lange lijn is traag**: 0,75 MiB/s vanaf Hetzner naar Canada (RTT 122 ms),
+      terwijl OpenSSH `sftp` 16,6 MiB/s haalt. De SFTP-stream van files_external (phpseclib) wacht na
+      elk klein blok op antwoord. Oplossing: pack-ranges bij SFTP met phpseclib's eigen `get()`
+      (veel verzoeken tegelijk) lezen in plaats van via de stream, zoals bij S3. 1 TB duurt nu ~2 weken.
+      Na meten: de grootste oorzaak was het netwerk (cubic, zie 14): met BBR gaat de restore van 0,75
+      naar 2,3 MiB/s, een hele pack lezen 4-5 MiB/s. Meer verzoeken in één stream (DEPTH 16/32) gaf geen
+      duidelijke winst. Verder komen vraagt meerdere verbindingen tegelijk: naar **1.1.0**.
+  14. **Uploaden over een lange lijn**: backup naar OVH S3 Warschau vanaf Canada (RTT 114 ms) haalt
+      ~1 MiB/s met één pack tegelijk; `aws s3 cp` (multipart, parallel) 6 MiB/s. Meerdere packs tegelijk
+      uploaden of S3 multipart. Minder dringend dan 13 (restore).
+      Oorzaak netwerk (met Sysop): pakketverlies trans-Atlantisch + cubic in de VM; met BBR gaat één
+      PUT van 2,4 naar 7,5 MiB/s, ng_backup van ~1 naar ~1,6 MiB/s (rest = serieel lezen/uploaden).
+      Tip over BBR in de README gezet. Let op: PVE02 staat in Canada; een restore in de EU gaat sneller.
+  15. DR-document: in het Docker-voorbeeld "je containernaam" (`docker ps`) i.p.v. `nextcloud`.
+  16. Grote restore (VM 980, snapshot aa7cce8d van de Storage Box) stopte na 22 uur met
+      `Not found: packs/26/2642ef39…`. Oorzaak: de wekelijkse opruiming van nc01 (zo 18-10) heeft
+      dat pakket tijdens de restore omgepakt (blob staat nu in `389567b7…`); de herstelserver had de
+      index van vóór de opruiming. Productie heel: `backup:verify` op nc01 OK (150.639 bestanden,
+      316.830 blobs). Opgelost in rc2: bij een mislukte pakketlezing de index herladen en de blob
+      lezen waar hij nu staat (test `testRestoreFollowsPacksRepackedByAnotherServer`).
+  **Kleine DR-test met rc2 (2026-10-18), volautomatisch geslaagd:** bron VM 981 (NC 34, PostgreSQL,
+  51 GB, Mail met gesynct account, Deck uitgeschakeld, Calendar/Contacts, admin_audit) → OVH S3 →
+  verse VM 982 met alleen de DR-gids en `--install-apps`: apps vanzelf geïnstalleerd, 10 Deck-tabellen
+  aangemaakt, 15 FK's in orde, 23.519/23.519 checksums gelijk, agenda/contact/mail/bord terug.
+  Restore 1 u 47 vanuit Warschau naar Canada (met BBR). Lokaal slaagt de test ook op SQLite en MariaDB.
+  **Daarna verplicht:** een tweede volledige restore op een verse VM, alleen met de HOWTO en de
+  nieuwe opties, zonder handwerk. Pas als die in één keer slaagt: 1.0.0.
+
+- **Later (geen versie):** optie om de sleutel niet op de locatie op te slaan (kit is dan de enige
+  kopie; uitdrukkelijke waarschuwing). Primaire object storage en External-storage-koppelingen
+  meenemen via de opslaglaag (§3.4; nu niet ondersteund, zie README "Known limitations").
+- **Open:** of de bevestigingscode van de kit dubbelop is (nog niet over besloten).
+
+Doorgeschoven naar **v1.3.0** (fase 3, niet meer fase 2): in-place volledige restore
+(eigen restore-modus i.p.v. onderhoudsmodus) en zelfbediening voor gebruikers (eigen bestanden
+terugzetten vanuit de Files-app).
+
 **Let op (ontdekt 2026-10-05):** Nextcloud's eigen `info.xsd` staat voor `<version>` alleen
 `[0-9]+(\.[0-9]+){0,2}` toe — geen `-alpha`/`-beta`/`-rc`-achtervoegsel. De stabiliteitsaanduiding
 uit deze tabel gaat dus niet in `info.xml` (dat blijft gewoon oplopend, bijv. `0.1.0`), maar in de

README.md

@@ -2,12 +2,22 @@
 
 Encrypted, incremental backups of Nextcloud (database, configuration and data) with restore
 from the web interface. Works without shell access: no external programs, no extra PHP
-extensions beyond sodium. Runs on Nextcloud All-in-One, regular installations and hosted
-Nextcloud.
+extensions beyond sodium for ng_backup itself. Runs on Nextcloud All-in-One, regular
+installations and hosted Nextcloud. (Choosing SMB as a storage backend is the one exception:
+see "Storage backend experiences" below — that requirement comes from files_external, not from
+ng_backup, and applies to any Nextcloud app that writes to an SMB share.)
 
-**Status: in development (phase 1). Not ready for production use.** See `PLAN.md` for the design.
+**Status: 1.0.2, stable.** Disaster recovery has been tested on real installations (see "Tested
+disaster recoveries" below). See "Known limitations" below, `PLAN.md` for the design and
+`docs/HOWTO.md` for a step-by-step guide from setup to a tested restore. Server lost? See
+`docs/DISASTER-RECOVERY.md`.
 
-License: AGPL-3.0-or-later.
+If you like NG Backup, don't forget to give the app a star in the
+[app store](https://apps.nextcloud.com/apps/ng_backup) and this repository a star on GitHub!
+
+License: AGPL-3.0-or-later. Developed and sponsored by [Ensembia](https://www.ensembia.com).
+Need help restoring a backup after a crash? Ensembia offers paid restore assistance:
+[www.ensembia.com](https://www.ensembia.com).
 
 ## How it works
 
@@ -19,16 +29,41 @@ License: AGPL-3.0-or-later.
   leaves the server, and streamed straight to the location: no local copy, no double disk space.
   Unchanged files are not read again; only new data is uploaded.
 - The database is dumped through Nextcloud's own connection, inside one consistent transaction.
+- A backup runs in short steps from Nextcloud's background jobs, and every step saves where it
+  got to. A restart of the server or the containers does not lose the run: it continues at the
+  next background job run. Tested on a production Nextcloud AIO instance: a 1 TB full backup over
+  SMB carried on through the nightly AIO update, which restarts every container.
 - Restores go through Nextcloud, so overwritten files keep their old content as a version and
   removed files go to the trash.
 
+## Requirements
+
+- **Background jobs on system cron.** NG Backup runs backups in steps from Nextcloud's
+  background job, so a backup only moves forward when that job runs. Choosing "Cron" under
+  **Administration settings → Basic settings → Background jobs** is not enough on its own: it
+  tells Nextcloud that the system will call it, so you also need a cron line that does. Without
+  it scheduled backups do not run; the admin page and `occ backup:status` warn about it, and a
+  backup started with "Back up now" only moves on while the NG Backup page stays open.
+  `occ backup:run` in a terminal works without cron (it runs in the foreground).
+  - Regular server: `crontab -u www-data -e` and add
+    `*/5 * * * * php -f /var/www/nextcloud/cron.php` (your Nextcloud path).
+  - Docker (the official `nextcloud` image): on the host, `crontab -e` as root and add
+    `*/5 * * * * docker exec -u www-data <container> php -f /var/www/html/cron.php`, or add a
+    service with the same image and `entrypoint: /cron.sh` to your `docker-compose.yml`.
+  - Nextcloud All-in-One already runs cron.
+
+  After a few minutes, the Background jobs section shows that the last job ran just now. See the
+  [Nextcloud documentation on background jobs](https://docs.nextcloud.com/server/latest/admin_manual/configuration_server/background_jobs_configuration.html).
+- A storage location: S3 or compatible, SFTP, WebDAV, SMB (needs the PHP `smbclient` extension,
+  see below), FTP or a local path.
+
 ## Quick start
 
 ```
 occ backup:key:init --label="Safe"                 # first passphrase, deletion delay (default 7 days)
 occ backup:key:slot:add --label="CTO"              # optional second and third passphrase
 occ backup:key:slot:add --label="Head of IT"
-occ backup:key:kit --output=/root/ng_backup-kit.json
+occ backup:key:kit --output=/var/tmp/ng_backup-kit.json
 occ backup:key:confirm
 occ backup:target:add offsite amazons3 -a amazons3::accesskey -o bucket=... -o key=... -o secret=...
 occ backup:run
@@ -43,9 +78,19 @@ All backups of an installation are encrypted with one master key.
 - The **server** keeps the master key, encrypted with the instance secret, so scheduled backups
   and restores work without anyone typing a passphrase. Any administrator can restore from the
   web interface. Consequence: whoever fully controls the server can read the backups; whoever
-  only gets hold of the backup location cannot.
-- For a **restore on a new server** (disaster recovery) you need the **recovery kit** and **one
-  passphrase**. The kit contains the master key, encrypted separately with each passphrase.
+  only gets hold of the backup location cannot, as long as the passphrases are strong (see below).
+- The **location holds the key too**, by design (like restic and Borg in repokey mode): its
+  `config` file contains the master key, encrypted separately with each passphrase (Argon2id),
+  the same as in the recovery kit. Without a passphrase it is of no use, but whoever can read the
+  location can try passphrases offline. **Your passphrase is therefore the actual key**: it must
+  be at least 16 characters; five or more random words are a good choice.
+- The **recovery kit** is your own copy of that encrypted key. Still keep it off the server and
+  off the location: an attacker who gets write access to the location can damage or delete its
+  `config` file on purpose, and without the kit that makes every backup there unreadable.
+- For a **restore on a new server** (disaster recovery) you currently need the **recovery kit**
+  and **one passphrase**.
+- Planned: an option to not store the key on the location at all. Then the kit is the only copy,
+  and losing it means losing every backup; that option will come with an explicit warning.
 - Up to **three passphrases** ("slots") can open the key, so one person leaving or dying does not
   lock the company out. A suggested setup:
 
@@ -59,7 +104,8 @@ All backups of an installation are encrypted with one master key.
   a single slot is possible, but then that one passphrase is a single point of failure.
 - When a holder leaves, give their slot a new passphrase (`occ backup:key:slot:replace`), download
   the new kit and confirm it. Note: an old kit together with the old passphrase still opens the
-  same master key; to revoke it completely, start new locations with a new key.
+  same master key; to revoke it completely, start new locations with a new key. This is noted on
+  the backlog and will be addressed in a future version (key rotation).
 - Downloading the kit, and every change to the slots, requires the administrator's password, is
   written to the audit log and is announced to all administrators.
 
@@ -104,7 +150,31 @@ What you should do on the location (strongly recommended):
 - **Files and folders** of a user: in the web interface or `occ backup:restore`, into a new folder
   ("Restored <date>"), merged into the original place, or replacing it.
 - **Raw restore** of any path (for example `config/`) to a local directory: `occ backup:restore ... --to-directory=DIR`.
-- **Whole server** (disaster recovery onto a fresh installation): planned for phase 2.
+- **Whole server** (disaster recovery onto a fresh installation): `occ backup:restore:full`, see
+  [docs/DISASTER-RECOVERY.md](docs/DISASTER-RECOVERY.md). It runs in maintenance mode, so that
+  nobody and no background job writes into the instance while it is being replaced.
+- **One user** (account, settings, files, calendars, contacts via user_migration): `occ backup:user:backup` and
+  `occ backup:user:restore`, replacing the account or restoring it as `<uid>-bak`. See the how-to.
+
+**Without shell access** (a hosted Nextcloud where you cannot run `occ`): files and folders can be
+restored in the web interface. Restoring a whole user or the whole server needs `occ`, so on such
+hosting it is something your provider (or whoever has shell access) runs. A restore mode that
+works without maintenance mode, and so from the web interface, is on the roadmap.
+
+## Tested disaster recoveries
+
+Full restores onto a fresh server, following only [the guide](docs/DISASTER-RECOVERY.md):
+
+| Backup | Location | Database | Result |
+|---|---|---|---|
+| Production, about 1 TB, 150,000 files (Nextcloud All-in-One) | Hetzner Storage Box (SFTP), Germany → Canada | PostgreSQL → PostgreSQL | 150,622 files restored in about 25 h (13-14 MiB/s), sample identical |
+| The same, 1.0.2 | Hetzner Storage Box (SMB), Germany → Canada | PostgreSQL → PostgreSQL | 150,755 files restored in about 29 h (7-13 MiB/s), going on after a lost connection; sample identical, empty folders not restored ([#27](https://github.com/dillardblom/ng_backup/issues/27)) |
+| 138 GB simulation: 20 users, calendars, contacts, mail, shares, team folders with an ACL, versions, trash | OVH S3, Warsaw → Canada | MariaDB → PostgreSQL | all 15,772 files and every database count identical |
+| The same | OVH S3 | MariaDB → MariaDB | all 15,772 files and every database count identical |
+| The same | Hetzner Storage Box (SMB), Germany → Canada | MariaDB → SQLite | all 15,772 files and every database count identical (27.6 h, about 1.5 MB/s) |
+| 51 GB test instance | OVH S3 | PostgreSQL → PostgreSQL | 23,519/23,519 checksums identical |
+
+The integration tests restore across every pair of PostgreSQL, MariaDB and SQLite.
 
 ## Storage backend experiences
 
@@ -119,13 +189,152 @@ Contributions welcome via PR — add what you ran into with your own provider.
   verified whether this also applies to a Hetzner Storage Box **main** account (only tested with a
   sub-account so far) — if you've tried a main account, please say so in a PR.
 
+- **Hetzner Storage Box over WebDAV and SMB (sub-accounts, 2026-10-07):** both work end to end
+  (backup, incremental run, restore of a folder, verify), tested from outside the Hetzner network
+  with about 66 MiB of data. In the Hetzner Console, enable WebDAV or SMB support for the
+  sub-account, and "External reachability" when your server is not in the Hetzner network.
+  WebDAV: host `https://uXXXXX-subN.your-storagebox.de`, and the `root`
+  must be a folder that already exists (or empty): WebDAV does not create missing parent folders,
+  so a root that doesn't exist yet fails `backup:target:add` with `Sabre\HTTP\ClientHttpException:
+  Conflict`. SMB: share = the sub-account name, port 445 must be reachable from your server (it was
+  from a home connection here, but some providers block it), and the `smbclient` PECL extension is
+  required (see the SMB entry below). Both have a noticeable fixed cost per run: an incremental run
+  that uploads nothing took about 20 s over WebDAV and 50 s over SMB. Over WebDAV, Nextcloud gives
+  every request at most 30 s by default, also an upload of a whole 32 MiB pack: on an upload
+  slower than about 9 Mbit/s a backup fails with `cURL error 28: Operation timed out`. Raise the
+  limit with `occ config:system:set davstorage.request_timeout --value=600 --type=integer`.
+
+- **FTP, server-dependent absolute-path handling:** files_external's FTP backend always builds
+  absolute paths (e.g. `MKD /repo`) for the configured root, never relative ones. `atmoz/sftp`-style
+  `vsftpd` test servers (chrooted) can reject that with a generic "create directory operation
+  failed", even though a plain `ftp_mkdir()` with a *relative* path on the same server succeeds;
+  `pure-ftpd` accepts the absolute form fine. If a working FTP server rejects ng_backup's writes,
+  try a different FTP server implementation before assuming the backend itself is broken.
+
+- **SMB/CIFS *lists* as available with just the `smbclient` CLI binary, but does not actually
+  work for ng_backup without the `smbclient` PECL extension too.** files_external falls back to a
+  shell-wrapped `smbclient` process when the native extension is missing, which registers the
+  backend in `occ backup:target:backends` fine, but that fallback's stream cannot seek. ng_backup
+  reads blobs back by byte range while backing up, so even the very first (small) backup fails
+  with `Seek failed in packs/...`. Install the extension (`libsmbclient-dev` + `pecl install
+  smbclient` + `docker-php-ext-enable smbclient` on Debian-based images), not just the CLI tool —
+  the backend being listed is not proof it will work here. Once the extension is present it works
+  the same as any other backend; no ng_backup-specific config beyond host/share/user/password.
+
+- **Backups over a long distance (high latency):** on Linux, the default TCP congestion control
+  (cubic) slows a single connection down a lot on a long line with some packet loss. From Canada to
+  an S3 bucket in Warsaw (114 ms), one upload went from 2.4 to 7.5 MiB/s after switching the
+  server (or the VM/container host where TCP ends) to BBR:
+  `sysctl -w net.core.default_qdisc=fq net.ipv4.tcp_congestion_control=bbr`
+  (`modprobe tcp_bbr` first; make it permanent in `/etc/sysctl.d/`).
+  A full restore over SFTP reads the packs ahead on a second connection, with many requests in
+  flight. A server that handles parallel reads well (not a Hetzner Storage Box, which gets slower)
+  can be read on more connections: `occ config:app:set ng_backup restore_sftp_connections
+  --value=4` (at most 8; the server must allow that many plus one at once for the user).
+
+- **OVH Object Storage (S3, Warsaw, 2026-10):** works with the `amazons3` backend (path style,
+  region `waw`). A full backup of 1 TB from Germany ran at about 7 MiB/s, from Canada about
+  6 MiB/s with BBR; a check of a 1 TB backup took 3.5 minutes (index files are fetched 16 at a
+  time); a restore of 138 GB from Warsaw to Canada took about 6 hours. Turn on versioning and
+  Object Lock on the bucket (see above); OVH charges no egress.
+
+- **Hetzner Storage Box over SFTP, full restore:** about 13-14 MiB/s from Germany to Canada
+  (122 ms) with the read-ahead of 1.0.0-rc.4; without it about 2.8 MiB/s. A Storage Box gets
+  slower with several connections reading at once (4-6 MiB/s for 2-4 connections, it reads from
+  disks), so one extra connection is the default. A Storage Box drops an SFTP connection that
+  stayed quiet for a while without telling the client; NG Backup checks and replaces it.
+
+- **SMB speed:** on a local network (Samba, no delay) a backup ran at about 25 MB/s and a
+  restore at about 28 MiB/s. Over a long line SMB waits for an answer to each request: from
+  Canada to a Storage Box in Germany (130 ms) about 2.6 MiB/s for a backup and 1.6 MiB/s for a
+  restore, and connecting a location with an existing backup reads its index at about one file a
+  second. SMB is meant for a local network; use SFTP or S3 for a location far away. When
+  `pecl install smbclient` fails (pecl.php.net was unreachable for hours on 2026-10-21), the
+  extension builds from its source: `libsmbclient-php` on GitHub, `phpize && ./configure && make
+  && make install`, then `docker-php-ext-enable smbclient`.
+
+- **NFS is not a files_external backend at all.** Mount the NFS export on the server yourself
+  (e.g. via `/etc/fstab` or a systemd `.mount` unit) and point ng_backup's `local` backend at the
+  mount point; ng_backup never mounts or unmounts anything on its own, so an NFS mount dropping
+  mid-run behaves like any other local-path failure (the run resumes). See PLAN.md 3.5 for why NFS
+  can't be driven from PHP directly.
+
+## Roadmap
+
+What is planned, without dates. Ideas and votes are welcome in the
+[issues](https://github.com/dillardblom/ng_backup/issues); if something you need is listed here,
+a 👍 on its issue helps decide what comes first.
+
+**1.0.3**
+- Empty folders in the backup and the restore
+  ([#27](https://github.com/dillardblom/ng_backup/issues/27)).
+
+**1.1.0**
+- Restore without the recovery kit: the backup key from the location itself, opened with one of
+  your passphrases.
+- A schedule per location, also "every N hours".
+- Locations backed up one after the other instead of at the same time.
+- A note on a restore point that you can change afterwards.
+- Pinning a restore point, so the retention policy never removes it (for example the one from
+  before an upgrade).
+- An option to pause heavy background jobs (such as Memories, Recognize or the Preview
+  Generator) while a backup runs.
+- Faster backups: reading and uploading at the same time.
+
+**Later**
+- A full restore onto the existing installation, without first installing a fresh Nextcloud, in a
+  restore mode of its own instead of maintenance mode, so that it can also run from the web
+  interface (for hosted Nextcloud without shell access).
+- Users restoring their own files from the Files app.
+- Primary object storage and External Storage mounts (see Known limitations).
+- An option not to keep the backup key on the location (the recovery kit is then the only copy).
+
+## Known limitations
+
+On the backlog; know them before you rely on NG Backup:
+
+- **Empty folders do not come back.** A backup only records files, so a folder without files is
+  not restored. To be fixed in 1.0.3
+  ([#27](https://github.com/dillardblom/ng_backup/issues/27)).
+- **Only the data directory is backed up.** Object storage as primary storage (`objectstore` in
+  `config.php`) is not supported: a backup refuses to start there. Folders mounted through the
+  External storage app are not in the data directory and are **not included**, without a warning.
+  Back them up separately. On the roadmap: reading files through Nextcloud's storage layer, which
+  covers both, with external mounts optional per mount (`PLAN.md` section 3.4).
+- **Very large instances** (well over 1 TB, millions of files): the blob index, cleanup, browsing a
+  snapshot in the web interface and per-user export manifests are held in memory. Expect high
+  memory use there; reports from such instances are very welcome.
+- **One location, one server.** Never let two Nextcloud servers write to the same location (for
+  example a disaster recovery test server pointed at the production location): they can break each
+  other's catalog, and the location is then refused as possibly tampered with. Test a disaster
+  recovery against a copy of the location, or only read from it.
+- **Removing a passphrase slot does not revoke access.** The master key stays the same, so someone
+  with an old recovery kit and that slot's passphrase can still decrypt the location if they can
+  read it. Key rotation is not available yet.
+- **Rollback before a disaster recovery is not detected.** A fresh server has no record of the
+  newest catalog generation, so a location rolled back to an older state looks valid there.
+- Location passwords passed with `-o password=...` are visible in the process list and shell
+  history while the command runs.
+- Temporary files of a restore into a user's files end up in that user's trash.
+- **Restoring a whole user or the whole server needs `occ`** (shell access); see "Without shell
+  access" above.
+- **`--install-apps` depends on the app store.** Nextcloud downloads the whole app list (about
+  38 MB) and gives up after 120 seconds; on a slow day apps are not installed. The restore then
+  lists them: install them afterwards with `occ app:install`, their data is restored already.
+- A pack whose index upload failed stays on the location until removed by hand.
+
 ## Commands
 
 | Command | Purpose |
 |---|---|
 | `backup:key:init`, `backup:key:kit`, `backup:key:confirm` | create the key, recovery kit, confirmation |
 | `backup:key:slots`, `backup:key:slot:add/replace/remove` | passphrase slots |
-| `backup:target:backends/add/list/remove/append-only` | backup locations |
-| `backup:run`, `backup:status`, `backup:list` | back up, status, restore points |
+| `backup:target:backends/add/edit/list/remove/append-only` | backup locations |
+| `backup:run`, `backup:status`, `backup:list` | back up, status (runs of the last 7 days; `--all` for all), restore points |
+| `backup:cancel <run>` | stop a running backup |
 | `backup:browse`, `backup:restore` | browse and restore |
 | `backup:retention`, `backup:prune`, `backup:trash`, `backup:trash:restore` | retention, cleanup, trash |
+| `backup:verify` | checksum audit of a restore point (`--deep` downloads and decrypts everything) |
+| `backup:restore:full` | whole-server restore onto a fresh installation (after `backup:key:import`) |
+| `backup:key:import` | import a recovery kit on a fresh installation |
+| `backup:user:backup`, `backup:user:list`, `backup:user:restore` | one user via user_migration (asks before installing it); list the exports |

appinfo/info.xml

@@ -3,18 +3,63 @@
     xsi:noNamespaceSchemaLocation="https://apps.nextcloud.com/schema/apps/info.xsd">
     <id>ng_backup</id>
     <name>NG Backup</name>
-    <summary>Encrypted, incremental backups of your Nextcloud with restore from the web interface</summary>
-    <description><![CDATA[Alpha: feature-complete for scheduled, encrypted, incremental backups to
-S3/SFTP/WebDAV/local, with restore of files and folders from the web interface and occ. Meant for
-testing on a copy of production (dev, test, staging) -- not yet for production use, and full
-disaster recovery is not implemented yet. See the recovery kit section of the README before
-relying on this for anything.]]></description>
-    <version>0.1.0</version>
+    <summary>Encrypted, incremental backups of your Nextcloud — files, database and config — with restore from the web interface</summary>
+    <description><![CDATA[Back up your whole Nextcloud — data directory, database and configuration — encrypted and
+incremental, to storage you choose. Restore single files, folders, a user, or the whole server from
+the web interface or `occ`. No shell access or external tools needed, so it also runs on Nextcloud
+All-in-One and hosted Nextcloud.
+
+**Where to**
+- S3 and S3-compatible storage, SFTP, WebDAV, SMB, FTP, Swift or a local path (NFS mount), through
+  the connection code of the External storage app. A location is never mounted and never shows up
+  in Files.
+
+**How**
+- Deduplicated, compressed and encrypted (XChaCha20-Poly1305) on the server before upload, streamed
+  straight to the location: no local copy, no double disk space. Unchanged files are not read again.
+- Database dump through Nextcloud's own connection, in one consistent transaction (PostgreSQL,
+  MySQL/MariaDB, SQLite).
+- Runs in short steps from the background jobs, so a server or container restart does not lose a
+  running backup.
+- Daily schedule, retention policy, and `occ backup:verify` (optionally `--deep`) to check that a
+  backup can be read.
+
+**Safe**
+- Up to three passphrases plus a recovery kit; the passphrase is the actual key.
+- Deletion delay and append-only locations against ransomware or a compromised server; S3 object
+  lock supported.
+- Admin notifications on failures, stale backups and changes to keys and locations.
+
+**Restore**
+- Files and folders into a new folder, merged, or replacing the original — through Nextcloud, so
+  overwritten files keep a version and removed ones go to the trash.
+- One user (account, files, calendars, contacts) via user_migration.
+- The whole server onto a fresh installation (disaster recovery).
+
+NG Backup needs Nextcloud's background jobs on system cron (a real cron line, not only the setting).
+Read "Known limitations" in the README before you rely on it, and test a restore. Feedback is very
+welcome: use the "Share your experience" link on the admin page.
+
+**If you like NG Backup, don't forget to give the app a star in the app store and the
+[repository](https://github.com/dillardblom/ng_backup) a star on GitHub!**
+
+Developed and sponsored by [Ensembia](https://www.ensembia.com). We can offer (paid) assistance if
+you need help with restoring a backup after a crash.]]></description>
+    <version>1.0.2</version>
     <licence>agpl</licence>
-    <author>Dillard Blom</author>
+    <author mail="dillard.blom@ensembia.com">Dillard Blom</author>
     <namespace>NgBackup</namespace>
+    <documentation>
+        <admin>https://github.com/dillardblom/ng_backup/blob/main/docs/HOWTO.md</admin>
+    </documentation>
     <category>tools</category>
+    <website>https://github.com/dillardblom/ng_backup</website>
     <bugs>https://github.com/dillardblom/ng_backup/issues</bugs>
+    <repository type="git">https://github.com/dillardblom/ng_backup</repository>
+    <screenshot>https://raw.githubusercontent.com/dillardblom/ng_backup/v1.0.2/screenshots/1-backups.png</screenshot>
+    <screenshot>https://raw.githubusercontent.com/dillardblom/ng_backup/v1.0.2/screenshots/2-restore.png</screenshot>
+    <screenshot>https://raw.githubusercontent.com/dillardblom/ng_backup/v1.0.2/screenshots/3-settings.png</screenshot>
+    <screenshot>https://raw.githubusercontent.com/dillardblom/ng_backup/v1.0.2/screenshots/4-bin.png</screenshot>
     <dependencies>
         <php min-version="8.1"/>
         <lib>sodium</lib>
@@ -29,9 +74,11 @@ relying on this for anything.]]></description>
         <command>OCA\NgBackup\Command\KeyConfirm</command>
         <command>OCA\NgBackup\Command\TargetBackends</command>
         <command>OCA\NgBackup\Command\TargetAdd</command>
+        <command>OCA\NgBackup\Command\TargetEdit</command>
         <command>OCA\NgBackup\Command\TargetList</command>
         <command>OCA\NgBackup\Command\TargetRemove</command>
         <command>OCA\NgBackup\Command\RunBackup</command>
+        <command>OCA\NgBackup\Command\CancelRun</command>
         <command>OCA\NgBackup\Command\Status</command>
         <command>OCA\NgBackup\Command\ListSnapshots</command>
         <command>OCA\NgBackup\Command\Browse</command>
@@ -47,6 +94,12 @@ relying on this for anything.]]></description>
         <command>OCA\NgBackup\Command\KeySlotAdd</command>
         <command>OCA\NgBackup\Command\KeySlotReplace</command>
         <command>OCA\NgBackup\Command\KeySlotRemove</command>
+        <command>OCA\NgBackup\Command\BackupUser</command>
+        <command>OCA\NgBackup\Command\RestoreUser</command>
+        <command>OCA\NgBackup\Command\ListUserExports</command>
+        <command>OCA\NgBackup\Command\KeyImport</command>
+        <command>OCA\NgBackup\Command\RestoreFull</command>
+        <command>OCA\NgBackup\Command\Verify</command>
     </commands>
     <settings>
         <admin>OCA\NgBackup\Settings\Admin</admin>

appinfo/routes.php

@@ -18,10 +18,13 @@ return [
 		['name' => 'AdminApi#untrash', 'url' => '/api/targets/{targetId}/trash/{snapshotId}', 'verb' => 'POST'],
 		['name' => 'AdminApi#backends', 'url' => '/api/backends', 'verb' => 'GET'],
 		['name' => 'AdminApi#addTarget', 'url' => '/api/targets', 'verb' => 'POST'],
+		['name' => 'AdminApi#targetSettings', 'url' => '/api/targets/{id}/settings', 'verb' => 'GET'],
+		['name' => 'AdminApi#updateTarget', 'url' => '/api/targets/{id}', 'verb' => 'PUT'],
 		['name' => 'AdminApi#removeTarget', 'url' => '/api/targets/{id}', 'verb' => 'DELETE'],
 		['name' => 'AdminApi#testTarget', 'url' => '/api/targets/{id}/test', 'verb' => 'POST'],
 		['name' => 'AdminApi#setTargetLimit', 'url' => '/api/targets/{id}/limit', 'verb' => 'PUT'],
 		['name' => 'AdminApi#startBackup', 'url' => '/api/backups', 'verb' => 'POST'],
+		['name' => 'AdminApi#tick', 'url' => '/api/tick', 'verb' => 'POST'],
 		['name' => 'AdminApi#setSchedule', 'url' => '/api/schedule', 'verb' => 'PUT'],
 		['name' => 'AdminApi#snapshots', 'url' => '/api/targets/{targetId}/snapshots', 'verb' => 'GET'],
 		['name' => 'AdminApi#browse', 'url' => '/api/targets/{targetId}/snapshots/{snapshotId}/browse', 'verb' => 'GET'],

docs/DISASTER-RECOVERY.md

@@ -0,0 +1,162 @@
+# Disaster recovery: your server is gone
+
+Your Nextcloud server is lost. You have a new, empty server. These are the steps to get your
+Nextcloud back from an NG Backup location. Do them in this order.
+
+## What you need
+
+- [ ] The **recovery kit** file (`ng_backup-kit.json`) and **one passphrase** of it.
+- [ ] The **connection details of the backup location**: host, user, password or keys, bucket, folder.
+- [ ] A new server with the **same Nextcloud major version** as the old one (for example 34),
+      a database (PostgreSQL, MySQL/MariaDB or SQLite; it may differ from the old one) and room for
+      the whole backup plus a margin.
+- [ ] **Shell access** to the new server, to run `occ` (on a hosted Nextcloud without it, your
+      provider runs these steps).
+- [ ] A list of the apps that are **not in the app store** (your own builds, apps copied in by
+      hand). Keep their packages somewhere safe beforehand.
+
+No kit? If the location still holds its `config` file, the key is there too, but this version
+can only import it from a kit. Keep the kit off the server, next to the passphrase.
+
+## Steps
+
+**1. Install a fresh Nextcloud** of the same major version. Create an admin account. Do not add
+users or files.
+
+**2. Do not let background jobs run yet.** A new Nextcloud runs them on page visits (AJAX).
+Switch that off:
+
+    occ background:cron
+
+As long as no cron is set up, nothing runs. Check that none is:
+
+- Regular server: `sudo crontab -u www-data -l`. If it shows a line with `cron.php`, remove it
+  for now with `sudo crontab -u www-data -e` (put it back in step 9).
+- Docker Compose with a cron service: `docker compose stop cron`.
+- Nextcloud All-in-One: cron runs inside the Nextcloud container; leave it. It does no harm here:
+  the restore keeps NG Backup's own settings of the new server, so it does not start backups.
+
+This keeps the new server quiet (no mail syncs, no notifications, no backups) until it is ready.
+
+**3. Install NG Backup** (the same version or newer) and enable it.
+
+**4. Import the backup key.** Copy the kit to the new server so the web server user can read it.
+
+From your own computer:
+
+    scp ng_backup-kit.json root@newserver:/tmp/
+
+Then on the server, one of:
+
+    chown www-data /tmp/ng_backup-kit.json                                    # regular server
+    docker cp /tmp/ng_backup-kit.json <container>:/tmp/ && \
+      docker exec <container> chown www-data /tmp/ng_backup-kit.json          # Docker
+
+`<container>` is the name of your Nextcloud container: `docker ps` shows it (for example
+`nextcloud-aio-nextcloud`, or `myproject-nextcloud-1` with Docker Compose).
+
+Import it; you type the passphrase yourself:
+
+    occ backup:key:import /tmp/ng_backup-kit.json
+
+It shows the key fingerprint: it must match the one of your old server (on the recovery kit).
+
+**5. Add the backup location** with the same details as before. On a large backup this first reads
+the index and shows how far it is, for example
+`Reading the index: 6,913/26,791 files (25%), about 12 min left`.
+
+    occ backup:target:add offsite sftp -a password::password -o host=... -o user=... -o password=... -o root=... --path=...
+
+If it says "No backup key yet", the key is not imported. Run step 4:
+
+    occ backup:key:import /tmp/ng_backup-kit.json
+
+Do **not** run `backup:key:init`, even though the message suggests it: that makes a brand new key,
+and your backups were encrypted with the old one. NG Backup then refuses the location ("created
+with a different key").
+
+**6. List the restore points** and pick one, normally the newest:
+
+    occ backup:list offsite
+
+**7. Start the restore, and let it install the apps.**
+
+    occ backup:restore:full offsite <snapshot> --install-apps
+
+`--install-apps` first installs every app the old server had enabled from the app store (or
+switches it on, if it is part of Nextcloud). Tables of apps that are missing or were removed long
+ago are created from the backup, so they do not stop the restore.
+
+At the end it lists the apps it could not install, usually your own builds that are not in the
+app store. Copy those into `custom_apps` and enable them (`occ app:enable <app>`); their data is
+already restored.
+
+Backups made before 1.0.0-rc.2 do not record the structure of their tables. If the restore lists
+tables that do not exist here, install the apps they belong to and run it again, or leave them
+out with `--skip-missing-tables`.
+
+**8. Let the restore run.** It restores the database, then the data directory, and takes hours for
+a large backup. Nextcloud is in maintenance mode meanwhile, so nobody and no background job
+writes into it; the restore switches it off when it completes. (If you had switched maintenance
+mode on yourself before, it stays on: switch it off with `occ maintenance:mode --off` when ready.)
+
+If it stops halfway, maintenance mode stays on (the instance may be partly restored). Fix the cause,
+then switch maintenance mode off and run the restore again with `--force`, in one line (the message
+prints it): `occ maintenance:mode --off && occ backup:restore:full <location> <snapshot> --force`.
+It goes on where it stopped: data files that are already in place with the size and modification
+time of the backup are left, so only the rest comes from the location again (since 1.0.2; before,
+it started over). The database is restored again in full, which takes minutes. Leave out `--install-apps` this time, so that the instance is open only for the seconds until the
+restore has switched maintenance mode on again; apps the first run could not install are listed at
+the end of the restore, install those afterwards.
+If occ then says that Nextcloud or one of the apps requires an upgrade, the database is already
+the old server's: run `occ upgrade` first, then the same command with `--force`.
+
+**If the backup itself is damaged** (the restore stops with "Decryption failed", "Blob
+verification failed" or a file that is missing on the location), try an older restore point
+first. If none is better, `--salvage` restores whatever can be read:
+
+    occ backup:restore:full offsite <snapshot> --install-apps --salvage
+
+- Files that cannot be read are left out and listed at the end; everything else is restored.
+- If the database cannot be restored (its dump is damaged, or it does not fit this
+  installation), the database stays as the fresh installation made it, and the data directory
+  and config of the backup go to a folder of their own in the data directory,
+  `ngb-salvage-<snapshot>`. Each user's files are in `data/<user>/files` there: create the users
+  again and copy their files back by hand (then `occ files:scan --all`). Calendars, contacts and
+  shares are in the database and cannot be recovered this way.
+
+The command then ends with exit code 2 instead of 0. The same option exists for
+`occ backup:restore`, to restore single folders.
+
+**9. After the restore.** These worked in our tests:
+
+    occ upgrade
+    occ maintenance:repair
+    occ files:scan --all
+
+- Check `config/config.php`: `trusted_domains`, `overwrite.cli.url` and `overwritehost` come from
+  the old server; change them if the new server has another name. The database settings and the
+  data directory are kept from the new installation.
+- From Nextcloud All-in-One to a regular server: also check the cache settings (`memcache.*`,
+  `redis`), which point at AIO's containers.
+- Log in, open a few files, a calendar and a contact.
+- Empty folders do not come back: a backup only records files (to be fixed in 1.0.3, see
+  [issue #27](https://github.com/dillardblom/ng_backup/issues/27)). `occ files:scan` then removes
+  them from the file cache, so it reports them as removed.
+- Start background jobs again (cron), as in step 2 in reverse.
+
+**10. Point your domain at the new server** and check that clients reconnect.
+
+**11. Make a backup of the new server** to the same location (`occ backup:run offsite`). The old
+server must stay off: two servers must never write to the same location.
+
+## Never
+
+- Never let the old server write to the location again if it comes back. Switch its backups off
+  first.
+- Never give your passphrase to anyone. Nobody helping you needs it.
+
+## Help
+
+Stuck? [Ensembia](https://www.ensembia.com), the developer of NG Backup, offers paid help with
+restoring a backup after a crash.

docs/HOWTO.md

@@ -0,0 +1,189 @@
+# NG Backup how-to
+
+Step by step: from first install to a tested restore. All commands run as the web user
+(`sudo -u www-data php occ ...`, or `docker exec -u www-data <container> php occ ...` in
+All-in-One and Docker setups). Replace names in `<angle brackets>` with your own.
+
+## 1. Create the key and the recovery kit
+
+```
+occ backup:key:init --label="Main" --delete-delay-days=7
+occ backup:key:kit --output=/var/tmp/ng_backup-kit.json
+occ backup:key:confirm -u <your-admin-uid> --code=<code shown> --confirm="Yes, I confirm"
+```
+
+- The passphrase protects the backup: the location stores the key encrypted with it, so whoever
+  can read the location can try to guess it. Use at least 16 characters (five or more random
+  words work well) and keep it somewhere other than this server.
+- Optional: extra passphrases for other people with `occ backup:key:slot:add --label="..."`.
+  Any one passphrase is enough to restore. Removing a slot later does not revoke access for someone
+  who kept an old kit and that passphrase (see "Known limitations" in the README).
+- The recovery kit (`/var/tmp/ng_backup-kit.json` above) is also required for disaster recovery. The web
+  user writes it there; then move it off the server as root, next to the passphrase, and delete the
+  copy in `/var/tmp`. The location holds the same encrypted key, but keep the kit anyway: if
+  someone damages or deletes the key on the location, the kit is the only way back in.
+
+## 2. Add a backup location
+
+NG Backup uses Nextcloud's External storage backends. Check what your server supports first:
+
+```
+occ backup:target:backends
+```
+
+Examples:
+
+```
+occ backup:target:add offsite amazons3 -a amazons3::accesskey -o bucket=<bucket> -o key=<key> -o secret=<secret>
+occ backup:target:add nas sftp -a password::password -o host=<host> -o user=<user> -o password=<pw> -o root=home
+occ backup:target:add local local -a null::null -o datadir=/mnt/backup
+```
+
+- **SFTP on a Hetzner Storage Box sub-account:** use `-o root=home`, not `/` (see README).
+- **FTP:** use a server that accepts absolute paths (for example `pure-ftpd`).
+- **SMB:** requires the native `smbclient` PHP extension. The CLI binary alone is not enough (see README).
+  `backup:target:add` refuses SMB when the extension is missing.
+- **NFS:** not a backend of its own. Mount the export on the server and use the `local` backend
+  with the mount point as `datadir`.
+
+Verify the location before relying on it:
+
+```
+occ backup:target:list
+occ backup:status
+```
+
+A backup that hangs or takes far too long can be stopped. `backup:status` shows the run number;
+the command waits until the step in progress is finished, then the process working on the run
+stops, and the next cleanup removes what it stored:
+
+```
+occ backup:cancel 7
+```
+
+Changed password, new host name, or moved the repository? Edit the location instead of adding a
+new one, so its history stays (in the web interface: **Edit** next to the location). The new
+settings must lead to the same repository; options you do not pass keep their value:
+
+```
+occ backup:target:edit nas -o password=<new pw>
+```
+
+## 3. Run the first backup
+
+```
+occ backup:run offsite -l first
+occ backup:list
+```
+
+Later runs upload only changed data. An unchanged run uploads (almost) nothing; the output shows
+the number of uploaded bytes, so check that value when you test incremental behaviour.
+
+Schedule `occ backup:run` from system cron (or use the Administration settings, if you prefer).
+
+## 4. Check the backup regularly
+
+```
+occ backup:verify offsite <snapshot>          # shallow: all blocks are present
+occ backup:verify offsite <snapshot> --deep   # also downloads and decrypts every block
+```
+
+Run the deep check at least once after setting up a location, and after changing it.
+
+## 5. Restore files and folders
+
+In the web interface, or with occ:
+
+```
+occ backup:browse offsite <snapshot>
+occ backup:restore offsite <snapshot> data/<uid>/files/Docs --mode=new-folder
+occ backup:restore offsite <snapshot> data/<uid>/files/Docs --mode=merge
+occ backup:restore offsite <snapshot> data/<uid>/files/Docs --mode=replace
+occ backup:restore offsite <snapshot> config --to-directory=/var/tmp/restore-config
+```
+
+- `new-folder` (default): puts the files in "Restored <date>" next to the original. Safest choice.
+- `merge`: adds missing files, keeps current ones.
+- `replace`: overwrites the folder. Replaced files keep their old content as a version, and removed
+  files go to the trash.
+- `--to-directory`: writes raw files to a local directory (for example `config/`).
+
+## 6. Back up and restore one user
+
+Needs the `user_migration` app. NG Backup asks before installing it:
+
+```
+occ backup:user:backup offsite <uid>
+occ backup:user:list offsite [<uid>]                                  # the exports and their manifest
+occ backup:user:restore offsite users/<uid>/<exportId>               # replace (default)
+occ backup:user:restore offsite users/<uid>/<exportId> --mode=as-backup
+```
+
+- `backup:user:restore` needs the manifest path that `backup:user:backup` prints at the end
+  (`users/<uid>/<exportId>`); `backup:user:list` shows it again. A user id alone also works when
+  that user has exactly one export on the location. With more (a `replace` restore adds a safety
+  export), the command lists them and you pass one.
+
+- If `user_migration` is missing, the command asks to install and enable it. For non-interactive
+  use, add `--install-user-migration` to approve that explicitly. The command stops after the
+  installation; run it once more.
+- `replace` first makes a safety export of the current account, then recreates the user under the
+  same id. When the account exists, the command asks first; in scripts, add `--force`. Shares to
+  others and data of apps without a user_migration migrator are not restored, so prefer
+  `as-backup` when in doubt: it restores into `<uid>-bak` and leaves the original untouched.
+- A restore onto a server where the user does not exist works. Calendars and address books get an
+  internal name with the prefix `migrated-` (for example `migrated-personal`). That prefix comes from
+  user_migration and cannot be turned off. The user can change the display name of these calendars and
+  address books in the app as usual; the internal name stays as it is.
+- **Settings:** on restore, `user_migration` imports only the app settings on its own allowlist
+  (for example calendar view and reminder settings). Other app settings of the user are skipped.
+  NG Backup reuses `user_migration`'s importer, so this list is not extended.
+- Keep the last few exports per user: `occ backup:retention --user-last=3`.
+
+## 7. Disaster recovery: restore the whole server
+
+Server lost? Follow the step-by-step [DISASTER-RECOVERY.md](DISASTER-RECOVERY.md).
+
+Use a fresh Nextcloud installation of the same major version, with NG Backup installed and
+the same location available. For a test, use a **copy** of the location: two servers writing to one
+location break each other's catalog.
+
+```
+occ backup:key:import /path/ng_backup-kit.json --passphrase-file=/path/passphrase
+occ backup:target:add offsite <backend> ...          # same details as on the original server
+occ backup:list offsite                              # the snapshots must be listed
+occ backup:restore:full offsite <snapshot>
+```
+
+The command refuses on an installation that already has more than one user, and asks before it
+starts; `--force` skips both (also needed to rerun it after it stopped halfway).
+
+Afterwards, check that users, files and the database are complete, and run a backup of the restored
+server. The restored installation keeps its own app configuration and secret.
+
+Stuck? [Ensembia](https://www.ensembia.com), the developer of NG Backup, offers paid help with
+restoring a backup after a crash. You keep your passphrase to yourself: it is never needed by
+anyone helping you.
+
+## 8. Retention
+
+```
+occ backup:retention --last=3 --daily=7 --weekly=4 --monthly=12
+occ backup:prune offsite --dry-run   # show first
+occ backup:prune offsite             # apply the policy; forgotten snapshots go to the trash first
+occ backup:trash                  # list the trash
+occ backup:trash:restore offsite <id>
+```
+
+Snapshots are kept according to the policy, and their data is deleted only after the deletion delay
+(set with `backup:key:init --delete-delay-days`). `occ backup:prune offsite --dry-run` shows what would be
+removed without changing anything.
+
+## 9. Checklist before you rely on it
+
+- [ ] Key created, passphrase stored off-server, recovery kit stored off-server
+- [ ] Location added; `backup:status` shows it reachable
+- [ ] First backup done and listed in `backup:list`
+- [ ] `backup:verify --deep` succeeds
+- [ ] One file restore tested (`new-folder`)
+- [ ] Disaster recovery tested on a second, fresh installation (or in a test environment)

lib/Backend/ExternalStorageFactory.php

@@ -72,6 +72,10 @@ final class ExternalStorageFactory {
 			throw new BackendException("Auth mechanism $authId does not fit backend $backendId");
 		}
 
+		if (is_string($options['private_key'] ?? null)) {
+			$options['private_key'] = self::normalizePrivateKey($options['private_key']);
+		}
+
 		$config = new StorageConfig();
 		$config->setBackend($backend);
 		$config->setAuthMechanism($auth);
@@ -86,4 +90,22 @@ final class ExternalStorageFactory {
 		$storage = $backend->wrapStorage($storage);
 		return $auth->wrapStorage($storage);
 	}
+
+	/**
+	 * An OpenSSH-format private key with its line breaks restored. Up to Nextcloud 34
+	 * (phpseclib 2) a key whose newlines were lost or turned into spaces, e.g. on its way through
+	 * a shell or a form, still loaded; Nextcloud 35 (phpseclib 3) refuses it with "Unable to read
+	 * key" (#24). The key itself is not changed, so it is fixed when it is used, not when stored.
+	 * Other formats (PEM, PKCS#8) still load as they are and are returned unchanged.
+	 */
+	public static function normalizePrivateKey(string $key): string {
+		if (!preg_match('/-----BEGIN OPENSSH PRIVATE KEY-----(.*?)-----END OPENSSH PRIVATE KEY-----/s', $key, $m)) {
+			return $key;
+		}
+		$body = (string)preg_replace('/\s+/', '', $m[1]);
+		if (!preg_match('#^[A-Za-z0-9+/]+=*$#', $body)) {
+			return $key;
+		}
+		return "-----BEGIN OPENSSH PRIVATE KEY-----\n" . chunk_split($body, 70, "\n") . "-----END OPENSSH PRIVATE KEY-----\n";
+	}
 }

lib/Backend/GetsOneByOne.php

@@ -0,0 +1,40 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\Backend;
+
+/** IBackend::getMany() and getRanges() for a backend where reading one after the other costs nothing extra. */
+trait GetsOneByOne {
+	/**
+	 * @param list<string> $paths
+	 * @return \Generator<string, string>
+	 */
+	public function getMany(array $paths): \Generator {
+		foreach ($paths as $path) {
+			$fh = $this->get($path);
+			try {
+				$data = stream_get_contents($fh);
+			} finally {
+				fclose($fh);
+			}
+			if ($data === false) {
+				throw new BackendException('Read failed for ' . $path);
+			}
+			yield $path => $data;
+		}
+	}
+
+	/**
+	 * @param list<array{0:string, 1:int, 2:int}> $ranges
+	 * @return \Generator<int, string>
+	 */
+	public function getRanges(array $ranges): \Generator {
+		foreach ($ranges as $i => [$path, $offset, $length]) {
+			yield $i => $this->getRange($path, $offset, $length);
+		}
+	}
+}

lib/Backend/IBackend.php

@@ -22,9 +22,30 @@ interface IBackend {
 	/** @return resource readable stream of the whole object */
 	public function get(string $path);
 
+	/**
+	 * Many small objects whole, in the order given (the repository's index files). A backend
+	 * where every request costs a round trip can fetch them several at a time.
+	 *
+	 * @param list<string> $paths
+	 * @return \Generator<string, string> contents by path
+	 * @throws BackendException for an object that cannot be read
+	 */
+	public function getMany(array $paths): \Generator;
+
 	/** @return string bytes [$offset, $offset + $length) of the object (used to fetch single blobs from a pack) */
 	public function getRange(string $path, int $offset, int $length): string;
 
+	/**
+	 * Many byte ranges, in the order given (blobs spread over many packs, such as the tree
+	 * segments of a backup). A backend where every request costs a round trip can fetch them
+	 * several at a time.
+	 *
+	 * @param list<array{0:string, 1:int, 2:int}> $ranges [path, offset, length] each
+	 * @return \Generator<int, string> contents by position in $ranges
+	 * @throws BackendException for a range that cannot be read
+	 */
+	public function getRanges(array $ranges): \Generator;
+
 	public function exists(string $path): bool;
 
 	/**
@@ -37,5 +58,15 @@ interface IBackend {
 	/** @return list<string> object paths below $prefix (recursive) */
 	public function list(string $prefix): array;
 
+	/**
+	 * Object paths directly in $dir, for a folder that only holds objects (index/, snapshots/,
+	 * catalog/, trash/info/). One listing, without checking the type of every entry: on a remote
+	 * storage list() costs a round trip per entry, which for index/ (one file per pack) grows
+	 * with the size of the repository.
+	 *
+	 * @return list<string>
+	 */
+	public function listFiles(string $dir): array;
+
 	public function delete(string $path): void;
 }

lib/Backend/IReadsAhead.php

@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\Backend;
+
+/**
+ * A backend that can read many byte ranges ahead of use, several at a time over connections of
+ * its own (a full restore, where one connection at a time is bound by the round trip).
+ */
+interface IReadsAhead {
+	/** Whether readAhead() is worth planning for: false when it would return null anyway. */
+	public function canReadAhead(): bool;
+
+	/**
+	 * The ranges in the order given, each as a local stream at offset 0 holding its bytes, read a
+	 * few ranges ahead of the one the caller is at. A stream is closed when the generator is
+	 * resumed. Null for a range that could not be read this way (a missing object, a server or
+	 * connection error): the caller reads it the usual way, which reports why.
+	 *
+	 * @param list<array{0:string, 1:int, 2:int}> $ranges [path, offset, length] each
+	 * @param string $spool an existing local directory for the files that hold the ranges
+	 * @return \Generator<int, resource|null>|null by position in $ranges; null when this backend
+	 *                                             cannot read ahead now
+	 */
+	public function readAhead(array $ranges, string $spool): ?\Generator;
+}

lib/Backend/LocalBackend.php

@@ -8,6 +8,8 @@ declare(strict_types=1);
 namespace OCA\NgBackup\Backend;
 
 final class LocalBackend implements IBackend {
+	use GetsOneByOne;
+
 	public function __construct(
 		private string $root,
 	) {
@@ -33,11 +35,16 @@ final class LocalBackend implements IBackend {
 			if ($out === false) {
 				throw new BackendException('Cannot write ' . $path);
 			}
+			$expected = StorageBackend::remaining($stream);
 			if (stream_copy_to_stream($stream, $out) === false || !fflush($out)) {
 				throw new BackendException('Write failed for ' . $path);
 			}
 			fclose($out);
 			$out = false;
+			clearstatcache(true, $tmp);
+			if ($expected !== null && filesize($tmp) !== $expected) {
+				throw new BackendException('Incomplete write for ' . $path);
+			}
 			if (!rename($tmp, $target)) {
 				throw new BackendException('Cannot finalise ' . $path);
 			}
@@ -94,7 +101,7 @@ final class LocalBackend implements IBackend {
 		$result = [];
 		$it = new \RecursiveIteratorIterator(new \RecursiveDirectoryIterator($base, \FilesystemIterator::SKIP_DOTS));
 		foreach ($it as $file) {
-			if ($file->isFile() && !str_contains($file->getFilename(), '.part-')) {
+			if ($file->isFile() && !StorageBackend::isTemporary($file->getFilename())) {
 				$result[] = ltrim(substr($file->getPathname(), strlen($this->root)), '/');
 			}
 		}
@@ -102,6 +109,25 @@ final class LocalBackend implements IBackend {
 		return $result;
 	}
 
+	public function listFiles(string $dir): array {
+		$base = $this->abs($dir);
+		if (!is_dir($base)) {
+			return [];
+		}
+		$result = [];
+		$names = scandir($base);
+		if ($names === false) {
+			throw new BackendException('Cannot list ' . $dir);
+		}
+		foreach ($names as $name) {
+			if ($name !== '.' && $name !== '..' && !StorageBackend::isTemporary($name)) {
+				$result[] = trim($dir, '/') . '/' . $name;
+			}
+		}
+		sort($result);
+		return $result;
+	}
+
 	public function delete(string $path): void {
 		@unlink($this->abs($path));
 	}

lib/Backend/SftpRangeFetcher.php

@@ -0,0 +1,395 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\Backend;
+
+/**
+ * Reads byte ranges of files on an SFTP location ahead of use, over several connections at once,
+ * into local files (StorageBackend::readAhead(), for a full restore).
+ *
+ * A restore that reads its packs as it goes is bound by the round trip: from a Hetzner Storage
+ * Box to Canada (RTT 122 ms) it reached about 2.8 MiB/s, with the PHP process mostly waiting.
+ * Here every connection reads its own range with DEPTH requests in flight, ahead of the restore. PHP runs one thing at a time: while it waits for an answer on one connection, the
+ * answers of the others arrive in the kernel's buffers, so the connections still transfer at the
+ * same time.
+ *
+ * Uses the same internal phpseclib 2 methods as SftpReadStream (see SftpReadStream::connection()).
+ * The connections are this class's own, never the storage's: no other request goes over them.
+ * A range that fails (missing file, server error, a connection that breaks) comes out as null,
+ * for the caller to read the usual way; a broken connection is not used again.
+ */
+final class SftpRangeFetcher {
+	/**
+	 * Connections a full restore uses, unless the app setting restore_sftp_connections says
+	 * otherwise. One: a Hetzner Storage Box gave about 14 MiB/s on one connection with DEPTH
+	 * requests in flight, and 4-6 MiB/s on 2 or 4 (it reads from disks, and parallel readers make
+	 * them seek). On a line with packet loss to a server that handles parallel reads well, 4
+	 * connections did better (21 against 14 MiB/s).
+	 */
+	public const DEFAULT_CONNECTIONS = 1;
+	public const MAX_CONNECTIONS = 8;
+	/** READ requests in flight per connection. */
+	public const DEPTH = 32;
+	/** Ranges read ahead of the one the caller is at, in flight or waiting in the spool. */
+	public const AHEAD = 8;
+	/**
+	 * Seconds ready() waits for any connection to answer before it waits for each in turn: short,
+	 * in case a connection holds an answer where ready() does not look.
+	 */
+	private const SELECT_TIMEOUT = 1;
+	/** See SftpReadStream::CHUNK and MIN_CHUNK. */
+	private const CHUNK = 261120;
+	private const MIN_CHUNK = 32768;
+
+	private const FXP_OPEN = 3;
+	private const FXP_CLOSE = 4;
+	private const FXP_READ = 5;
+	private const FXP_STATUS = 101;
+	private const FXP_HANDLE = 102;
+	private const FXP_DATA = 103;
+	private const FXF_READ = 1;
+	private const FX_OK = 0;
+
+	/** Connections that broke and are replaced, at most, in one restore. */
+	public const MAX_RECONNECTS = 20;
+
+	private const OPEN = 0;
+	private const READ = 1;
+	private const CLOSE = 2;
+
+	/** @var array<int, int> READ size per connection, lowered when a server answers less than asked */
+	private array $chunks = [];
+	/** @var array<int, SftpRangeJob> the range each busy connection reads */
+	private array $jobs = [];
+	/** @var array<int, resource|null> ranges read (or failed) and not yet given to the caller */
+	private array $done = [];
+	private int $requestId = 0x4e520000;
+	/** Connections replaced so far (see MAX_RECONNECTS). */
+	public int $reconnects = 0;
+
+	/**
+	 * @param array<int, object> $connections phpseclib 2 connections with their SFTP channel open
+	 * @param list<array{0:string, 1:int, 2:int}> $ranges paths below $root
+	 */
+	private function __construct(
+		private array $connections,
+		private string $root,
+		private array $ranges,
+		private string $spool,
+		private ?\Closure $connect = null,
+	) {
+		foreach (array_keys($connections) as $c) {
+			$this->chunks[$c] = self::CHUNK;
+		}
+	}
+
+	/**
+	 * See IReadsAhead::readAhead(). The connections are ended when the generator ends.
+	 *
+	 * @param list<object> $connections
+	 * @param list<array{0:string, 1:int, 2:int}> $ranges
+	 * @param (\Closure():?object)|null $connect a new connection in place of one that broke
+	 *                                         (null when it cannot be made)
+	 * @return \Generator<int, resource|null>
+	 */
+	public static function fetch(array $connections, string $root, array $ranges, string $spool, ?\Closure $connect = null): \Generator {
+		$fetcher = new self($connections, rtrim($root, '/'), $ranges, $spool, $connect);
+		try {
+			yield from $fetcher->run();
+		} finally {
+			$fetcher->end();
+		}
+	}
+
+	/** @return \Generator<int, resource|null> */
+	private function run(): \Generator {
+		$count = count($this->ranges);
+		$next = 0;
+		for ($want = 0; $want < $count; $want++) {
+			while (!array_key_exists($want, $this->done)) {
+				foreach (array_keys($this->connections) as $c) {
+					if (!isset($this->jobs[$c]) && $next < $count && $next < $want + self::AHEAD) {
+						$this->start($c, $next++);
+					}
+				}
+				if ($this->jobs === [] && !array_key_exists($want, $this->done)) {
+					// no connection left: the rest the usual way
+					$this->done[$want] = null;
+					$next = max($next, $want + 1);
+					break;
+				}
+				foreach ($this->ready() as $c) {
+					$this->step($c);
+				}
+			}
+			$fh = $this->done[$want];
+			unset($this->done[$want]);
+			try {
+				yield $want => $fh;
+			} finally {
+				if (is_resource($fh)) {
+					fclose($fh);
+				}
+			}
+		}
+	}
+
+	/**
+	 * The busy connections that have an answer waiting, so that a connection that waits for a
+	 * lost packet to be sent again does not hold up the others; all of them when the connections
+	 * do not tell (then they are taken in turn).
+	 *
+	 * @return list<int>
+	 */
+	private function ready(): array {
+		$sockets = [];
+		$ready = [];
+		foreach ($this->jobs as $c => $job) {
+			$sftp = $this->connections[$c];
+			$vars = get_object_vars($sftp); // only what is public: phpseclib 2's are
+			// Answers phpseclib has read already: the socket does not show them. Its request
+			// buffer holds whole answers read while it waited for another; its packet buffer and
+			// channel buffers hold what came in with the last packet it read (small answers, such
+			// as a CLOSE and the next OPEN, often arrive together).
+			$buffered = $vars['requestBuffer'] ?? null;
+			$channels = $vars['channel_buffers'] ?? null;
+			if ((is_array($buffered) && isset($job->queue[0]) && array_key_exists($job->queue[0][0], $buffered))
+				|| (is_string($vars['packet_buffer'] ?? null) && self::wholePacket($vars['packet_buffer']))
+				|| (is_array($channels) && array_filter($channels) !== [])) {
+				$ready[] = $c;
+				continue;
+			}
+			$socket = $vars['fsock'] ?? null;
+			if (!is_resource($socket)) {
+				return array_keys($this->jobs);
+			}
+			$sockets[$c] = $socket;
+		}
+		if ($ready !== [] || $sockets === []) {
+			return $ready;
+		}
+		$read = $sockets;
+		$write = null;
+		$except = null;
+		// Data in PHP's own buffer of a socket counts as readable. Nothing within the time:
+		// each in turn, where phpseclib's own timeout applies.
+		$n = @stream_select($read, $write, $except, self::SELECT_TIMEOUT);
+		return $n === false || $n === 0 ? array_keys($this->jobs) : array_keys($read);
+	}
+
+	/** Whether $buffer starts with a whole SFTP packet (length, then that many bytes). */
+	private static function wholePacket(string $buffer): bool {
+		$length = strlen($buffer) >= 4 ? unpack('N', $buffer) : false;
+		return is_array($length) && strlen($buffer) >= 4 + $length[1];
+	}
+
+	private function start(int $c, int $i): void {
+		[$path, $offset, $length] = $this->ranges[$i];
+		$fh = $this->spoolFile();
+		if ($fh === null) {
+			$this->done[$i] = null;
+			return;
+		}
+		if ($length <= 0) {
+			$this->done[$i] = $fh;
+			return;
+		}
+		$this->jobs[$c] = new SftpRangeJob($i, $fh, $offset, $offset + $length);
+		try {
+			$remote = $this->connections[$c]->_realpath($this->root . '/' . ltrim($path, '/'));
+			if (!is_string($remote)) {
+				$this->finish($c);
+				return;
+			}
+			$this->send($c, self::FXP_OPEN, pack('Na*N2', strlen($remote), $remote, self::FXF_READ, 0), self::OPEN);
+		} catch (\Throwable) {
+			$this->drop($c);
+		}
+	}
+
+	/** Take the oldest answer on connection $c, then keep its requests in flight. */
+	private function step(int $c): void {
+		$job = $this->jobs[$c];
+		[$id, $kind, $offset, $length] = array_shift($job->queue) ?? throw new \LogicException('no request in flight');
+		$sftp = $this->connections[$c];
+		try {
+			$response = $sftp->_get_sftp_packet($id);
+			if (!is_string($response)) {
+				throw new BackendException('SFTP connection lost');
+			}
+			$type = $sftp->packet_type;
+			if ($kind === self::OPEN) {
+				if ($type === self::FXP_HANDLE) {
+					$job->handle = substr($response, 4);
+				} else {
+					$job->failed = true; // missing, or no permission
+				}
+			} elseif ($kind === self::READ) {
+				if (!$job->failed) {
+					$this->received($c, $type, $response, $offset, $length);
+				}
+			} else {
+				$status = $type === self::FXP_STATUS && strlen($response) >= 4 ? unpack('N', $response) : false;
+				$closed = is_array($status) && $status[1] === self::FX_OK;
+				$this->finish($c);
+				if (!$closed) {
+					// handles might pile up on the server: not used again
+					$this->drop($c);
+				}
+				return;
+			}
+			$this->refill($c);
+		} catch (\Throwable) {
+			$this->drop($c);
+		}
+	}
+
+	private function received(int $c, int $type, string $response, int $offset, int $length): void {
+		$job = $this->jobs[$c];
+		$declared = strlen($response) >= 4 ? unpack('N', $response) : false;
+		$n = is_array($declared) ? $declared[1] : 0;
+		if ($type !== self::FXP_DATA || $n <= 0 || $n !== strlen($response) - 4 || $n > $length) {
+			// end of file before the end of the range, a server error or a malformed answer
+			$job->failed = true;
+			return;
+		}
+		if (fseek($job->fh, $offset - $job->start) !== 0 || fwrite($job->fh, substr($response, 4)) !== $n) {
+			$job->failed = true;
+			return;
+		}
+		$job->got += $n;
+		if ($n < $length) {
+			// a server that caps a READ: ask for the rest, and no more than it gives from now on
+			$job->redo[] = [$offset + $n, $length - $n];
+			$this->chunks[$c] = max(self::MIN_CHUNK, min($this->chunks[$c], $n));
+		}
+	}
+
+	/** Send READs until DEPTH are in flight; when nothing is left to ask for, close the file. */
+	private function refill(int $c): void {
+		$job = $this->jobs[$c];
+		if ($job->handle !== '' && !$job->failed) {
+			while (count($job->queue) < self::DEPTH) {
+				if ($job->redo !== []) {
+					[$offset, $length] = array_shift($job->redo);
+				} elseif ($job->next < $job->end) {
+					$offset = $job->next;
+					$length = min($this->chunks[$c], $job->end - $offset);
+					$job->next += $length;
+				} else {
+					break;
+				}
+				$packet = pack('Na*N3', strlen($job->handle), $job->handle, intdiv($offset, 4294967296), $offset % 4294967296, $length);
+				$this->send($c, self::FXP_READ, $packet, self::READ, $offset, $length);
+			}
+		}
+		if ($job->queue !== []) {
+			return;
+		}
+		if ($job->handle === '') {
+			$this->finish($c); // not opened: nothing to close
+			return;
+		}
+		$this->send($c, self::FXP_CLOSE, pack('Na*', strlen($job->handle), $job->handle), self::CLOSE);
+	}
+
+	private function send(int $c, int $type, string $packet, int $kind, int $offset = 0, int $length = 0): void {
+		$this->requestId = $this->requestId >= 0x7fffffff ? 0x4e520000 : $this->requestId + 1;
+		if (!$this->connections[$c]->_send_sftp_packet($type, $packet, $this->requestId)) {
+			throw new BackendException('SFTP connection failed while sending a request');
+		}
+		$this->jobs[$c]->queue[] = [$this->requestId, $kind, $offset, $length];
+	}
+
+	/** The range of connection $c is done: its stream for the caller, or null when it failed. */
+	private function finish(int $c): void {
+		$job = $this->jobs[$c];
+		unset($this->jobs[$c]);
+		if ($job->failed || $job->got !== $job->end - $job->start || !rewind($job->fh)) {
+			self::closeFile($job->fh);
+			$this->done[$job->i] = null;
+			return;
+		}
+		$this->done[$job->i] = $job->fh;
+	}
+
+	/** A connection in an unknown state: its range fails, and it is not used again. */
+	private function drop(int $c): void {
+		if (isset($this->jobs[$c])) {
+			$job = $this->jobs[$c];
+			unset($this->jobs[$c]);
+			self::closeFile($job->fh);
+			$this->done[$job->i] = null;
+		}
+		self::disconnect($this->connections[$c]);
+		unset($this->connections[$c]);
+		// A long restore outlives connections (a Storage Box drops one now and then): without a
+		// new one, the rest would be read the slow way.
+		if ($this->connect === null || $this->reconnects >= self::MAX_RECONNECTS) {
+			return;
+		}
+		$this->reconnects++;
+		try {
+			$new = ($this->connect)();
+		} catch (\Throwable) {
+			$new = null;
+		}
+		if (function_exists('OCP\Log\logger')) {
+			\OCP\Log\logger('ng_backup')->info($new === null
+				? 'Reading ahead: an SFTP connection broke and no new one could be made'
+				: 'Reading ahead: an SFTP connection broke; reading on with a new one');
+		}
+		if ($new !== null) {
+			$key = max(array_merge(array_keys($this->chunks), [-1])) + 1;
+			$this->connections[$key] = $new;
+			$this->chunks[$key] = self::CHUNK;
+		}
+	}
+
+	/** @return resource|null a new file in the spool, already unlinked: nothing is left behind if the process dies */
+	private function spoolFile() {
+		$path = $this->spool . '/' . bin2hex(random_bytes(8));
+		$fh = @fopen($path, 'x+b');
+		if ($fh === false) {
+			return null;
+		}
+		@unlink($path);
+		return $fh;
+	}
+
+	private function end(): void {
+		foreach ($this->jobs as $job) {
+			self::closeFile($job->fh);
+		}
+		foreach ($this->done as $fh) {
+			if (is_resource($fh)) {
+				fclose($fh);
+			}
+		}
+		$this->jobs = [];
+		$this->done = [];
+		foreach ($this->connections as $sftp) {
+			self::disconnect($sftp);
+		}
+		$this->connections = [];
+	}
+
+	private static function closeFile(mixed $fh): void {
+		if (is_resource($fh)) {
+			fclose($fh);
+		}
+	}
+
+	private static function disconnect(object $sftp): void {
+		try {
+			if (is_callable([$sftp, 'disconnect'])) {
+				$sftp->disconnect();
+			}
+		} catch (\Throwable) {
+		}
+	}
+}

lib/Backend/SftpRangeJob.php

@@ -0,0 +1,40 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\Backend;
+
+/**
+ * One range that SftpRangeFetcher reads on one connection.
+ *
+ * @internal
+ */
+final class SftpRangeJob {
+	public string $handle = '';
+	/** Offset of the next READ to send. */
+	public int $next;
+	/** @var list<array{int, int}> offset and length of parts to ask for again (after a short answer) */
+	public array $redo = [];
+	/** @var list<array{int, int, int, int}> request id, kind, offset and length, in the order sent */
+	public array $queue = [];
+	/** Bytes received. */
+	public int $got = 0;
+	public bool $failed = false;
+
+	/** @var resource the spool file that holds the range */
+	public $fh;
+
+	/** @param resource $fh */
+	public function __construct(
+		public int $i,
+		$fh,
+		public int $start,
+		public int $end,
+	) {
+		$this->fh = $fh;
+		$this->next = $start;
+	}
+}

lib/Backend/SftpReadStream.php

@@ -0,0 +1,628 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\Backend;
+
+/**
+ * Read stream for files_external's SFTP storage that keeps several READ requests in flight.
+ *
+ * files_external's own read stream asks for the next 256 KiB only after the previous one has
+ * arrived, so every request costs a full round trip: about 5 MB/s at 47 ms to a Hetzner Storage
+ * Box, whatever the line speed. With 8 requests in flight the same connection reached 15 MB/s.
+ * phpseclib's get() pipelines too, but only into memory or a local file, and only from offset 0.
+ *
+ * Talks to the storage's phpseclib connection through the same internal methods files_external's
+ * read stream uses (_send_sftp_packet, _get_sftp_packet, _realpath); open() returns null when the
+ * connection does not offer them (phpseclib 3 does not), and StorageBackend then falls back to the
+ * storage's own stream. A restore must rather be slow than fail: when a read fails halfway, the
+ * stream goes on from the same position with the storage's own stream. After MAX_FAILURES streams
+ * in a row failed, open() returns null for the rest of the process; one that works resets the count.
+ * Like that stream, it owns the connection while open: no other request may go over the same
+ * connection until it is closed (PackReaderGuard takes care of that for the repository).
+ */
+final class SftpReadStream {
+	private const PROTOCOL = 'ngbsftpread';
+	/** Requests in flight once a stream reads sequentially; it starts at one and doubles. */
+	public const DEPTH = 8;
+	/** Files read at once by readMany(): each holds a handle on the server while its batch runs. */
+	public const BATCH = 32;
+	/** Larger files are left to the usual read by readMany(), which holds every file in memory. */
+	private const MANY_MAX_BYTES = 16 * 1048576;
+	/** OpenSSH and the Hetzner Storage Box both answer at most 255 KiB per READ. */
+	private const CHUNK = 261120;
+	/** Every SFTP server must handle packets of this size (draft-ietf-secsh-filexfer-02, section 3). */
+	private const MIN_CHUNK = 32768;
+
+	private const FXP_OPEN = 3;
+	private const FXP_CLOSE = 4;
+	private const FXP_READ = 5;
+	private const FXP_STATUS = 101;
+	private const FXP_HANDLE = 102;
+	private const FXP_DATA = 103;
+	private const FXF_READ = 1;
+	private const FX_OK = 0;
+	private const FX_EOF = 1;
+
+	/**
+	 * READ size per connection, lowered when a server answers less than asked and then goes on, so
+	 * later streams over that connection ask for no more than it gives.
+	 *
+	 * @var \WeakMap<object, int>|null
+	 */
+	private static ?\WeakMap $chunks = null;
+	private static int $requestId = 0x4e470000;
+	/**
+	 * Connections whose server did not confirm closing a batch's files: readMany() is not used on
+	 * them again, so handles cannot pile up.
+	 *
+	 * @var \WeakMap<object, true>|null
+	 */
+	private static ?\WeakMap $noBatches = null;
+	/** Streams in a row that failed; at MAX_FAILURES only the storage's own stream is used. */
+	private static int $failures = 0;
+	public const MAX_FAILURES = 3;
+	/** Set by stream_open() when the connection failed rather than the file. */
+	private static bool $openBroke = false;
+	/** Why the last stream_open() failed on the connection. */
+	private static string $openCause = '';
+
+	/** @var resource|null set by PHP for stream wrappers */
+	public $context;
+
+	/**
+	 * The phpseclib connection. PHP creates stream wrappers without constructor arguments; it is
+	 * set in stream_open(), and no other method is called when that fails.
+	 *
+	 * @psalm-suppress PropertyNotSetInConstructor
+	 */
+	private object $sftp;
+	/** The storage and the path on it, to fall back to the storage's own stream. */
+	private ?object $storage = null;
+	private string $file = '';
+	/** @var resource|null the storage's own stream, once this one has failed */
+	private $fallback = null;
+	private string $handle = '';
+	/** Position of the reader: the first byte of $buffer. */
+	private int $pos = 0;
+	/** Offset of the next READ to send. */
+	private int $next = 0;
+	private string $buffer = '';
+	/** @var list<array{int, int, int}> request id, offset, length, in the order sent */
+	private array $inFlight = [];
+	private int $depth = 1;
+	private bool $eof = false;
+	/** This stream gave up on its own requests. */
+	private bool $failed = false;
+	/** The connection is in an unknown state: nothing more is sent over it or read from it. */
+	private bool $broken = false;
+	/** Length of the last short answer, until the next answer tells whether it was the end of the file. */
+	private ?int $shortAnswer = null;
+
+	/**
+	 * @param object $storage files_external's SFTP storage (getConnection(), getRoot())
+	 * @return resource|false|null the stream, false when the file cannot be opened, null when the
+	 *                             connection does not offer what this stream needs
+	 * @throws BackendException when the connection failed after the OPEN request went out: the
+	 *                          storage's own stream must not be tried on it, as it would take a
+	 *                          late answer to that request for its own
+	 */
+	public static function open(object $storage, string $path) {
+		if (self::$failures >= self::MAX_FAILURES) {
+			return null;
+		}
+		try {
+			$sftp = self::connection($storage);
+			if ($sftp === null) {
+				return null;
+			}
+			if (!in_array(self::PROTOCOL, stream_get_wrappers(), true)) {
+				stream_wrapper_register(self::PROTOCOL, self::class);
+			}
+			$root = rtrim((string)$storage->getRoot(), '/');
+			$context = stream_context_create([self::PROTOCOL => [
+				'session' => $sftp,
+				'path' => $root . '/' . ltrim($path, '/'),
+				'storage' => $storage,
+				'file' => $path,
+			]]);
+			self::$openBroke = false;
+			$fh = @fopen(self::PROTOCOL . '://file', 'r', false, $context);
+		} catch (\Throwable) {
+			// nothing was sent yet
+			self::$failures++;
+			return null;
+		}
+		if ($fh === false && self::openBroke()) {
+			throw new BackendException('SFTP connection failed while opening ' . $path . ': ' . self::$openCause);
+		}
+		return $fh;
+	}
+
+	/**
+	 * The storage's phpseclib connection, with its SFTP channel open, when it offers what these
+	 * streams (and SftpRangeFetcher) need; null otherwise.
+	 */
+	public static function connection(object $storage): ?object {
+		if (!is_callable([$storage, 'getConnection']) || !is_callable([$storage, 'getRoot'])) {
+			return null;
+		}
+		$sftp = $storage->getConnection();
+		// is_callable and get_object_vars from here only see what is public: phpseclib 3 has
+		// methods of these names neither public nor at all.
+		if (!is_object($sftp) || !is_callable([$sftp, '_send_sftp_packet']) || !is_callable([$sftp, '_get_sftp_packet'])
+			|| !is_callable([$sftp, '_realpath']) || !is_callable([$sftp, 'pwd'])
+			|| !array_key_exists('packet_type', get_object_vars($sftp))) {
+			return null;
+		}
+		// phpseclib opens the SFTP channel on its first SFTP call, not at login: on a fresh
+		// connection a packet sent directly would go nowhere. pwd() opens it like any call does.
+		if ($sftp->pwd() === false) {
+			return null;
+		}
+		return $sftp;
+	}
+
+	/**
+	 * Read many small files whole, BATCH at a time: the OPEN, READ and CLOSE requests of a batch
+	 * all go out before their answers are read, so a batch costs a few round trips instead of
+	 * four per file. Meant for files of up to a few hundred KiB (the repository's index files):
+	 * every file is held in memory.
+	 *
+	 * @param list<string> $paths below the storage's root
+	 * @return array<string, string|null>|null contents by path; null for a file this could not
+	 *                                         read (missing, or a server error), so the caller
+	 *                                         reads it the usual way; null for all when the
+	 *                                         connection does not offer what this needs
+	 * @throws BackendException when the connection failed while requests were out: the storage's
+	 *                          own stream must not be tried on it
+	 */
+	public static function readMany(object $storage, array $paths): ?array {
+		if (self::$failures >= self::MAX_FAILURES) {
+			return null;
+		}
+		try {
+			$sftp = self::connection($storage);
+			$root = $sftp === null ? '' : rtrim((string)$storage->getRoot(), '/');
+		} catch (\Throwable) {
+			self::$failures++;
+			return null;
+		}
+		if ($sftp === null || self::$noBatches?->offsetExists($sftp) === true) {
+			return null;
+		}
+		$result = array_fill_keys($paths, null);
+		foreach (array_chunk($paths, self::BATCH) as $batch) {
+			try {
+				[$read, $closed] = self::readBatch($sftp, $root, $batch);
+			} catch (\Throwable $e) {
+				self::$failures++;
+				// Answers to requests already sent may still arrive, and files_external would take
+				// them for its own: end the connection rather than leave it out of step.
+				self::disconnect($sftp);
+				throw $e instanceof BackendException ? $e : new BackendException('SFTP connection failed while reading ' . count($batch) . ' files: ' . $e->getMessage(), 0, $e);
+			}
+			foreach ($read as $path => $contents) {
+				$result[$path] = $contents;
+			}
+			if (!$closed) {
+				// The server did not confirm closing these files: no more batches on this
+				// connection, so handles cannot pile up. The rest is read the usual way.
+				self::noMoreBatches($sftp);
+				break;
+			}
+		}
+		self::$failures = 0;
+		return $result;
+	}
+
+	private static function noMoreBatches(object $sftp): void {
+		self::$noBatches ??= new \WeakMap();
+		self::$noBatches[$sftp] = true;
+	}
+
+	private static function disconnect(object $sftp): void {
+		try {
+			if (is_callable([$sftp, 'disconnect'])) {
+				$sftp->disconnect();
+			}
+		} catch (\Throwable) {
+		}
+	}
+
+	/** Requests of one kind for a whole batch, then their answers in order. @return list<array{int, string}> */
+	private static function exchange(object $sftp, int $type, array $packets): array {
+		$ids = [];
+		foreach ($packets as $packet) {
+			$id = self::nextId();
+			if (!$sftp->_send_sftp_packet($type, $packet, $id)) {
+				throw new BackendException('SFTP connection failed while sending a request');
+			}
+			$ids[] = $id;
+		}
+		$answers = [];
+		foreach ($ids as $id) {
+			$response = $sftp->_get_sftp_packet($id);
+			if (!is_string($response)) {
+				throw new BackendException('SFTP connection failed while waiting for an answer');
+			}
+			$answers[] = [$sftp->packet_type, $response];
+		}
+		return $answers;
+	}
+
+	/**
+	 * @param list<string> $batch
+	 * @return array{0: array<string, string>, 1: bool} the files read whole, and whether the
+	 *                                                  server confirmed closing every handle
+	 */
+	private static function readBatch(object $sftp, string $root, array $batch): array {
+		$opens = [];
+		$openPaths = [];
+		foreach ($batch as $path) {
+			$remote = $sftp->_realpath($root . '/' . ltrim($path, '/'));
+			if (is_string($remote)) {
+				$opens[] = pack('Na*N2', strlen($remote), $remote, self::FXF_READ, 0);
+				$openPaths[] = $path;
+			}
+			// a path that cannot be resolved is left to the caller's usual read
+		}
+		$handles = []; // path => handle
+		foreach (self::exchange($sftp, self::FXP_OPEN, $opens) as $i => [$type, $response]) {
+			if ($type === self::FXP_HANDLE) {
+				$handles[$openPaths[$i]] = substr($response, 4);
+			}
+			// any other answer (missing, no permission): the caller reads it the usual way
+		}
+		$data = array_fill_keys(array_keys($handles), '');
+		$reading = $handles;
+		while ($reading !== []) {
+			$length = self::chunk($sftp);
+			$reads = [];
+			foreach ($reading as $path => $handle) {
+				$offset = strlen($data[$path]);
+				$reads[] = pack('Na*N3', strlen($handle), $handle, intdiv($offset, 4294967296), $offset % 4294967296, $length);
+			}
+			$paths = array_keys($reading);
+			foreach (self::exchange($sftp, self::FXP_READ, $reads) as $i => [$type, $response]) {
+				$path = $paths[$i];
+				$declared = strlen($response) >= 4 ? unpack('N', $response) : false;
+				if ($type === self::FXP_DATA && is_array($declared) && $declared[1] > 0 && $declared[1] === strlen($response) - 4
+					&& $declared[1] <= $length && strlen($data[$path]) + $declared[1] <= self::MANY_MAX_BYTES) {
+					$data[$path] .= substr($response, 4); // more may follow: read on from there
+					continue;
+				}
+				unset($reading[$path]);
+				$status = $type === self::FXP_STATUS && is_array($declared) ? $declared[1] : null;
+				if ($status !== self::FX_EOF) {
+					// a server error, a malformed answer or a file too large for this: the caller
+					// reads it the usual way
+					unset($data[$path]);
+				}
+			}
+		}
+		$closes = [];
+		foreach ($handles as $handle) {
+			$closes[] = pack('Na*', strlen($handle), $handle);
+		}
+		$closed = true;
+		foreach (self::exchange($sftp, self::FXP_CLOSE, $closes) as [$type, $response]) {
+			$status = $type === self::FXP_STATUS && strlen($response) >= 4 ? unpack('N', $response) : false;
+			if (!is_array($status) || $status[1] !== self::FX_OK) {
+				$closed = false;
+			}
+		}
+		return [$data, $closed];
+	}
+
+	/** Test hook: forget the learned READ sizes and earlier failures. */
+	public static function reset(): void {
+		self::$chunks = null;
+		self::$noBatches = null;
+		self::$failures = 0;
+	}
+
+	public function stream_open(string $url, string $mode, int $options, ?string &$openedPath): bool {
+		$options = stream_context_get_options($this->context ?? stream_context_get_default())[self::PROTOCOL] ?? [];
+		if (!isset($options['session'], $options['path']) || !is_object($options['session'])) {
+			return false;
+		}
+		$this->sftp = $options['session'];
+		$storage = $options['storage'] ?? null;
+		$this->storage = is_object($storage) ? $storage : null;
+		$this->file = (string)($options['file'] ?? '');
+		try {
+			$remote = $this->sftp->_realpath((string)$options['path']);
+			if (!is_string($remote)) {
+				return false;
+			}
+			$id = self::nextId();
+			if (!$this->sftp->_send_sftp_packet(self::FXP_OPEN, pack('Na*N2', strlen($remote), $remote, self::FXF_READ, 0), $id)) {
+				return $this->connectionFailed('the request could not be sent');
+			}
+			$response = $this->sftp->_get_sftp_packet($id);
+		} catch (\Throwable $e) {
+			return $this->connectionFailed(get_class($e) . ': ' . $e->getMessage());
+		}
+		if (!is_string($response)) {
+			return $this->connectionFailed('no answer');
+		}
+		if ($this->sftp->packet_type !== self::FXP_HANDLE) {
+			return false; // an answer, but no handle: the file cannot be opened
+		}
+		$this->handle = substr($response, 4);
+		return true;
+	}
+
+	/** Not a missing file but a connection that does not behave as expected. */
+	private function connectionFailed(string $cause): bool {
+		self::$failures++;
+		self::$openBroke = true;
+		self::$openCause = $cause . self::connectionState($this->sftp);
+		// unknown state: closed, so that nothing else uses it (and the backend can build a new one)
+		self::disconnect($this->sftp);
+		return false;
+	}
+
+	/** What phpseclib knows about the connection, for an error message. */
+	private static function connectionState(object $sftp): string {
+		$state = [];
+		try {
+			if (is_callable([$sftp, 'isConnected'])) {
+				$state[] = 'connected: ' . ($sftp->isConnected() ? 'yes' : 'no');
+			}
+			if (is_callable([$sftp, 'getLastError'])) {
+				$last = (string)$sftp->getLastError();
+				if ($last !== '') {
+					$state[] = 'ssh: ' . $last;
+				}
+			}
+			if (is_callable([$sftp, 'getLastSFTPError'])) {
+				$last = (string)$sftp->getLastSFTPError();
+				if ($last !== '') {
+					$state[] = 'sftp: ' . $last;
+				}
+			}
+		} catch (\Throwable) {
+		}
+		return $state === [] ? '' : ' (' . implode('; ', $state) . ')';
+	}
+
+	/** Whether the last stream_open() failed on the connection; a call, as fopen() sets it. */
+	private static function openBroke(): bool {
+		return self::$openBroke;
+	}
+
+	public function stream_read(int $count): string|false {
+		if ($this->fallback !== null) {
+			return fread($this->fallback, $count);
+		}
+		while (strlen($this->buffer) < $count && !$this->eof) {
+			if (!$this->receive()) {
+				return $this->useFallback() ? $this->stream_read($count) : false;
+			}
+		}
+		$data = substr($this->buffer, 0, $count);
+		$this->buffer = substr($this->buffer, strlen($data));
+		$this->pos += strlen($data);
+		return $data;
+	}
+
+	public function stream_eof(): bool {
+		if ($this->fallback !== null) {
+			return feof($this->fallback);
+		}
+		return $this->eof && $this->buffer === '';
+	}
+
+	public function stream_tell(): int {
+		if ($this->fallback !== null) {
+			$pos = ftell($this->fallback);
+			return $pos === false ? $this->pos : $pos;
+		}
+		return $this->pos;
+	}
+
+	public function stream_seek(int $offset, int $whence = SEEK_SET): bool {
+		if ($this->fallback !== null) {
+			return fseek($this->fallback, $offset, $whence) === 0;
+		}
+		if ($whence === SEEK_CUR) {
+			$offset += $this->pos;
+		} elseif ($whence !== SEEK_SET) {
+			return false; // the size is never asked for, to save a round trip
+		}
+		if ($offset < 0) {
+			return false;
+		}
+		if ($this->failed) {
+			$this->pos = $offset;
+			return $this->useFallback();
+		}
+		if ($offset >= $this->pos && $offset - $this->pos <= strlen($this->buffer)) {
+			$this->buffer = substr($this->buffer, $offset - $this->pos);
+		} else {
+			$this->drain();
+			$this->buffer = '';
+			$this->next = $offset;
+			$this->eof = false;
+			$this->depth = 1;
+			$this->shortAnswer = null;
+		}
+		$this->pos = $offset;
+		return true;
+	}
+
+	/** @return array<int|string, int> */
+	public function stream_stat(): array {
+		return [];
+	}
+
+	public function stream_close(): void {
+		if (!$this->failed) {
+			self::$failures = 0;
+		}
+		$fallback = $this->fallback;
+		$this->fallback = null;
+		if ($fallback !== null) {
+			fclose($fallback);
+		}
+		$this->closeHandle();
+	}
+
+	/**
+	 * Go on with the storage's own stream from the current position, after a server error on this
+	 * one. The data still buffered is dropped and read again. False after a connection error, or
+	 * when that stream cannot be opened or positioned: then the read fails as it would have
+	 * without this class. Reopening by path is safe for a repository: packs and index files are
+	 * never rewritten, and every object is authenticated when it is decrypted.
+	 */
+	private function useFallback(): bool {
+		$this->closeHandle();
+		$this->buffer = '';
+		// files_external's stream takes whatever answer comes next on the connection: after a
+		// connection error, answers to this stream's requests may still be on their way.
+		if ($this->broken || $this->storage === null || !is_callable([$this->storage, 'fopen'])) {
+			return false;
+		}
+		try {
+			$fh = $this->storage->fopen($this->file, 'r');
+			if (!is_resource($fh)) {
+				return false;
+			}
+			if ($this->pos > 0 && fseek($fh, $this->pos) !== 0) {
+				fclose($fh);
+				return false;
+			}
+		} catch (\Throwable) {
+			return false;
+		}
+		$this->fallback = $fh;
+		return true;
+	}
+
+	private function closeHandle(): void {
+		$this->drain();
+		if ($this->handle !== '' && !$this->broken) {
+			try {
+				$id = self::nextId();
+				if (!$this->sftp->_send_sftp_packet(self::FXP_CLOSE, pack('Na*', strlen($this->handle), $this->handle), $id)
+					|| !is_string($this->sftp->_get_sftp_packet($id))) {
+					$this->broken = true;
+				}
+			} catch (\Throwable) {
+				$this->broken = true;
+			}
+			if ($this->broken) {
+				self::disconnect($this->sftp);
+			}
+		}
+		$this->handle = '';
+	}
+
+	/** Keep the pipeline full, then take the oldest answer. False on a connection or server error. */
+	private function receive(): bool {
+		if ($this->failed) {
+			return false;
+		}
+		try {
+			return $this->receiveOne();
+		} catch (\Throwable) {
+			$this->broken = true;
+			return $this->fail();
+		}
+	}
+
+	private function receiveOne(): bool {
+		while (count($this->inFlight) < $this->depth) {
+			$id = self::nextId();
+			$length = self::chunk($this->sftp);
+			$packet = pack('Na*N3', strlen($this->handle), $this->handle, intdiv($this->next, 4294967296), $this->next % 4294967296, $length);
+			if (!$this->sftp->_send_sftp_packet(self::FXP_READ, $packet, $id)) {
+				$this->broken = true;
+				return $this->fail();
+			}
+			$this->inFlight[] = [$id, $this->next, $length];
+			$this->next += $length;
+		}
+		[$id, $offset, $length] = array_shift($this->inFlight);
+		$response = $this->sftp->_get_sftp_packet($id);
+		if (!is_string($response)) {
+			$this->broken = true;
+			return $this->fail();
+		}
+		if ($this->sftp->packet_type === self::FXP_DATA) {
+			$data = substr($response, 4);
+			if ($data === '') {
+				return $this->fail();
+			}
+			$this->buffer .= $data;
+			$this->depth = min(self::DEPTH, $this->depth * 2);
+			if ($this->shortAnswer !== null) {
+				// More data after a short answer: that one was the server's cap, not the end.
+				// Never below what every server must support: a one-off small answer is no cap.
+				self::$chunks ??= new \WeakMap();
+				self::$chunks[$this->sftp] = max(self::MIN_CHUNK, min(self::chunk($this->sftp), $this->shortAnswer));
+				$this->shortAnswer = null;
+			}
+			if (strlen($data) < $length) {
+				// Fewer bytes than asked: the end of the file, or a server that caps a READ. The
+				// requests behind this one assumed a full answer, so drop them and ask again from here.
+				$this->drain();
+				$this->next = $offset + strlen($data);
+				$this->shortAnswer = strlen($data);
+			}
+			return true;
+		}
+		$status = $this->sftp->packet_type === self::FXP_STATUS ? unpack('N', $response) : false;
+		if (is_array($status) && ($status[1] ?? null) === self::FX_EOF) {
+			$this->eof = true;
+			$this->shortAnswer = null;
+			$this->drain();
+			return true;
+		}
+		return $this->fail();
+	}
+
+	private function fail(): bool {
+		$this->drain();
+		if (!$this->failed) {
+			self::$failures++;
+		}
+		$this->failed = true;
+		return false;
+	}
+
+	/** Read and drop the answers still on their way, so the connection is free again. */
+	private function drain(): void {
+		$inFlight = $this->inFlight;
+		$this->inFlight = [];
+		try {
+			foreach ($this->broken ? [] : $inFlight as [$id]) {
+				if (!is_string($this->sftp->_get_sftp_packet($id))) {
+					$this->broken = true;
+					break;
+				}
+			}
+		} catch (\Throwable) {
+			$this->broken = true;
+		}
+		if ($this->broken) {
+			// unknown state: closed, so that nothing else uses it (and the backend can build a new one)
+			self::disconnect($this->sftp);
+		}
+	}
+
+	private static function chunk(object $sftp): int {
+		$learned = self::$chunks?->offsetExists($sftp) === true ? self::$chunks->offsetGet($sftp) : null;
+		return is_int($learned) ? $learned : self::CHUNK;
+	}
+
+	private static function nextId(): int {
+		self::$requestId = self::$requestId >= 0x7fffffff ? 0x4e470000 : self::$requestId + 1;
+		return self::$requestId;
+	}
+}

lib/Backend/StorageBackend.php

@@ -14,23 +14,61 @@ use OCP\Files\Storage\IWriteStreamStorage;
  * IBackend on top of a Nextcloud storage object (from files_external or core), below a base
  * directory on that storage.
  */
-final class StorageBackend implements IBackend {
+final class StorageBackend implements IBackend, IReadsAhead {
 	/** Object stores write whole objects atomically; other storages get a temp name + rename. */
 	private bool $atomicPut;
+	/** SFTP: read through SftpReadStream, which keeps several requests in flight. */
+	private bool $sftpReads;
+	/** S3: many small reads go straight to the storage's S3 client, several at a time. */
+	private bool $s3Reads;
+	/** S3 requests in flight at once for getMany() and getRanges(). */
+	public const S3_CONCURRENCY = 16;
+	/**
+	 * Ranges readAhead() fetches at once over S3, each straight into a file in the spool (a range
+	 * is at most ReadAheadPlan::MAX_RANGE: the spool holds at most this many times that).
+	 */
+	public const S3_READ_AHEAD = 8;
+	/** Most ranges, and bytes, getRanges() holds in memory at once. */
+	private const RANGES_LOT = 64;
+	private const RANGES_LOT_BYTES = 64 * 1048576;
+	/** Seconds without a request after which an SFTP connection is checked before it is used. */
+	public const IDLE_CHECK = 60;
+	private float $lastUsed;
+	/** Connections readAhead() opens (see SftpRangeFetcher::DEFAULT_CONNECTIONS). */
+	public int $readAheadConnections = SftpRangeFetcher::DEFAULT_CONNECTIONS;
+	/** Times the storage was built anew after its connection died (for tests and diagnostics). */
+	public int $reconnects = 0;
 
+	/**
+	 * @param (\Closure():IStorage)|null $reconnect builds the same storage anew, with a new
+	 *                                             connection
+	 */
 	public function __construct(
 		private IStorage $storage,
 		private string $base = '',
+		bool $createBase = true,
+		private ?\Closure $reconnect = null,
 	) {
+		$this->lastUsed = microtime(true);
 		$this->base = trim($base, '/');
 		self::validate($this->base, true);
 		$this->atomicPut = $storage->instanceOfStorage(\OCA\Files_External\Lib\Storage\AmazonS3::class);
-		if ($this->base !== '') {
+		$this->sftpReads = $storage->instanceOfStorage(\OCA\Files_External\Lib\Storage\SFTP::class);
+		$this->s3Reads = $storage instanceof \OCA\Files_External\Lib\Storage\AmazonS3;
+		if ($createBase && $this->base !== '') {
 			$this->mkdirs($this->base);
 		}
 	}
 
+	/** A temporary upload of put(): "<name>.part-<8 hex>". */
+	public static function isTemporary(string $name): bool {
+		return preg_match('/\.part-[0-9a-f]{8}$/', $name) === 1;
+	}
+
 	public function put(string $path, $stream): void {
+		// not repeated on a new connection: the stream is (partly) read
+		$this->idleCheck();
+		$expected = self::remaining($stream);
 		$target = $this->abs($path);
 		$this->mkdirs(dirname($target));
 		$writeTo = $this->atomicPut ? $target : $target . '.part-' . bin2hex(random_bytes(4));
@@ -54,6 +92,10 @@ final class StorageBackend implements IBackend {
 			if (is_resource($stream)) {
 				fclose($stream);
 			}
+			// Some adapters report success after a short write or a failed flush: check the size.
+			if ($expected !== null && $this->storage->filesize($writeTo) !== $expected) {
+				throw new BackendException('Incomplete write for ' . $path);
+			}
 			if ($writeTo !== $target && !$this->storage->rename($writeTo, $target)) {
 				throw new BackendException('Cannot finalise ' . $path);
 			}
@@ -69,6 +111,19 @@ final class StorageBackend implements IBackend {
 	}
 
 	public function get(string $path) {
+		return $this->call(fn () => $this->open($path));
+	}
+
+	/** @return resource */
+	private function open(string $path) {
+		if ($this->sftpReads) {
+			$fh = SftpReadStream::open($this->storage, $this->abs($path));
+			if (is_resource($fh)) {
+				return $fh;
+			}
+			// null: not supported or failing for now; false: not opened, which need not mean
+			// missing. Either way the storage's own stream decides.
+		}
 		$fh = $this->storage->fopen($this->abs($path), 'r');
 		if ($fh === false) {
 			throw new BackendException('Not found: ' . $path);
@@ -76,7 +131,290 @@ final class StorageBackend implements IBackend {
 		return $fh;
 	}
 
+	/**
+	 * Over SFTP and S3 several at a time (SftpReadStream::readMany(), s3Fetch()); elsewhere one
+	 * after the other, over SMB in fewer round trips (smbWhole()).
+	 */
+	public function getMany(array $paths): \Generator {
+		$size = $this->s3Reads ? 16 * self::S3_CONCURRENCY : 8 * SftpReadStream::BATCH;
+		foreach (array_chunk($paths, $size) as $chunk) {
+			$fast = null;
+			if ($this->s3Reads) {
+				$this->idleCheck();
+				$fast = $this->s3Fetch(array_map(fn (string $p): array => [$p, null], $chunk));
+				$fast = $fast === null ? null : array_combine($chunk, array_map(fn (int $i): ?string => $fast[$i] ?? null, array_keys($chunk)));
+			} elseif ($this->sftpReads) {
+				$abs = array_map(fn (string $p): string => $this->abs($p), $chunk);
+				$fast = $this->call(fn () => SftpReadStream::readMany($this->storage, $abs));
+				$fast = $fast === null ? null : array_combine($chunk, array_map(fn (string $a): ?string => $fast[$a] ?? null, $abs));
+			}
+			foreach ($chunk as $path) {
+				// over SMB in fewer round trips, one after the other (smbWhole())
+				$data = $fast[$path] ?? $this->smbWhole($this->abs($path));
+				if ($data === null) {
+					// not read in the batch (or no batches here): the usual way, which also
+					// reports a missing file as such
+					$fh = $this->get($path);
+					try {
+						$data = stream_get_contents($fh);
+					} finally {
+						fclose($fh);
+					}
+					if ($data === false) {
+						throw new BackendException('Read failed for ' . $path);
+					}
+				}
+				yield $path => $data;
+			}
+		}
+	}
+
+	/** Over S3 several at a time (s3Fetch()); elsewhere one after the other. */
+	public function getRanges(array $ranges): \Generator {
+		$lot = [];
+		$bytes = 0;
+		foreach ($ranges as $i => $range) {
+			if ($lot !== [] && (count($lot) >= self::RANGES_LOT || $bytes + $range[2] > self::RANGES_LOT_BYTES)) {
+				yield from $this->rangesLot($lot);
+				$lot = [];
+				$bytes = 0;
+			}
+			$lot[$i] = $range;
+			$bytes += $range[2];
+		}
+		if ($lot !== []) {
+			yield from $this->rangesLot($lot);
+		}
+	}
+
+	/**
+	 * @param array<int, array{0:string, 1:int, 2:int}> $lot
+	 * @return \Generator<int, string>
+	 */
+	private function rangesLot(array $lot): \Generator {
+		$fast = null;
+		if ($this->s3Reads) {
+			$this->idleCheck();
+			$fast = $this->s3Fetch(array_map(fn (array $r): array => [$r[0], $r[1] . '-' . ($r[1] + $r[2] - 1)], $lot));
+		}
+		foreach ($lot as $i => [$path, $offset, $length]) {
+			$data = $fast[$i] ?? null;
+			// not read in the batch, or not all of it: the usual way, which also reports why
+			yield $i => ($data !== null && strlen($data) === $length) ? $data : $this->getRange($path, $offset, $length);
+		}
+	}
+
+	/**
+	 * Read objects (or byte ranges of them, "first-last") straight through the S3 client of
+	 * files_external's S3 storage, S3_CONCURRENCY at a time. Its own reads open a new HTTPS
+	 * connection per object, after a HEAD request: one after the other that is about two reads a
+	 * second, which made checking the index of a large repository take hours. What fails here
+	 * is left out of the result, for the caller to read the usual way (which reports the error).
+	 *
+	 * @param array<int, array{0:string, 1:?string}> $requests [path, range or null] by key
+	 * @return array<int, string>|null contents by key; null when the storage is not as expected
+	 * @psalm-suppress UndefinedClass the AWS SDK comes with Nextcloud, not with this app
+	 */
+	private function s3Fetch(array $requests): ?array {
+		try {
+			$s3 = $this->s3Client();
+			if ($s3 === null) {
+				return null;
+			}
+			[$client, $bucket, $sse] = $s3;
+			$results = [];
+			$keys = array_keys($requests); // the pool numbers results 0, 1, ...: mapped back below
+			$commands = (function () use ($requests, $client, $bucket, $sse): \Generator {
+				foreach (array_values($requests) as $n => [$path, $range]) {
+					$args = ['Bucket' => $bucket, 'Key' => trim($this->abs($path), '/')] + $sse;
+					if ($range !== null) {
+						$args['Range'] = 'bytes=' . $range;
+					}
+					yield $n => $client->getCommand('GetObject', $args);
+				}
+			})();
+			(new \Aws\CommandPool($client, $commands, [
+				'concurrency' => self::S3_CONCURRENCY,
+				'fulfilled' => function (mixed $result, int $n) use (&$results, $keys): void {
+					$results[$keys[$n]] = (string)$result['Body'];
+				},
+				'rejected' => static function (): void {
+				},
+			]))->promise()->wait();
+			return $results;
+		} catch (\Throwable) {
+			return null;
+		}
+	}
+
+	/**
+	 * files_external's S3 client, bucket and server-side encryption parameters; null when the
+	 * storage is not as expected.
+	 *
+	 * @return array{0: \Aws\S3\S3Client, 1: string, 2: array}|null
+	 * @psalm-suppress UndefinedClass the AWS SDK comes with Nextcloud, not with this app
+	 */
+	private function s3Client(): ?array {
+		/** @psalm-suppress UndefinedMethod, UndefinedThisPropertyFetch */
+		[$client, $bucket, $sse] = (function (): array {
+			$sse = method_exists($this, 'getServerSideEncryptionParameters') ? $this->getServerSideEncryptionParameters()
+				: (method_exists($this, 'getSSECParameters') ? $this->getSSECParameters() : []);
+			return [$this->getConnection(), $this->getBucket(), $sse];
+		})->call($this->storage);
+		return $client instanceof \Aws\S3\S3Client && is_string($bucket) ? [$client, $bucket, is_array($sse) ? $sse : []] : null;
+	}
+
+	/**
+	 * readAhead() over S3: S3_READ_AHEAD ranges at a time, fetched together straight into files in
+	 * the spool, then handed out in order. One request per range instead of one per blob (with a
+	 * new HTTPS connection each), and several at once: a restore is no longer bound by the round
+	 * trip. A range that could not be fetched is handed out as null (the caller reads it the
+	 * usual way, which reports why).
+	 *
+	 * @param list<array{0:string, 1:int, 2:int}> $ranges
+	 * @return \Generator<int, resource|null>|null
+	 * @psalm-suppress UndefinedClass the AWS SDK comes with Nextcloud, not with this app
+	 */
+	private function s3ReadAhead(array $ranges, string $spool): ?\Generator {
+		// before anything is fetched: an invalid path throws
+		$keys = array_map(fn (array $r): string => trim($this->abs($r[0]), '/'), $ranges);
+		try {
+			$s3 = $this->s3Client();
+		} catch (\Throwable) {
+			$s3 = null;
+		}
+		if ($s3 === null) {
+			return null;
+		}
+		[$client, $bucket, $sse] = $s3;
+		$this->idleCheck();
+		return (static function () use ($client, $bucket, $sse, $ranges, $keys, $spool): \Generator {
+			$prefix = rtrim($spool, '/') . '/s3-' . bin2hex(random_bytes(4)) . '-';
+			foreach (array_chunk(array_keys($ranges), self::S3_READ_AHEAD) as $lot) {
+				$files = [];
+				$commands = [];
+				foreach ($lot as $n => $i) {
+					$files[$i] = $prefix . $i;
+					$commands[$n] = $client->getCommand('GetObject', ['Bucket' => $bucket, 'Key' => $keys[$i],
+						'Range' => 'bytes=' . $ranges[$i][1] . '-' . ($ranges[$i][1] + $ranges[$i][2] - 1), 'SaveAs' => $files[$i]] + $sse);
+				}
+				$fetched = [];
+				try {
+					(new \Aws\CommandPool($client, $commands, [
+						'concurrency' => self::S3_READ_AHEAD,
+						'fulfilled' => function (mixed $result, int $n) use (&$fetched, $lot): void {
+							$fetched[$lot[$n]] = true;
+						},
+						'rejected' => static function (): void {
+						},
+					]))->promise()->wait();
+				} catch (\Throwable) {
+					// what was not fetched is read the usual way
+				}
+				try {
+					foreach ($lot as $i) {
+						clearstatcache(true, $files[$i]);
+						$fh = isset($fetched[$i]) && @filesize($files[$i]) === $ranges[$i][2] ? @fopen($files[$i], 'rb') : false;
+						@unlink($files[$i]); // the open stream keeps its data
+						yield $i => is_resource($fh) ? $fh : null;
+						if (is_resource($fh)) {
+							fclose($fh);
+						}
+					}
+				} finally {
+					// stopped halfway: the rest of this lot
+					foreach ($files as $file) {
+						@unlink($file);
+					}
+				}
+			}
+		})();
+	}
+
+	/**
+	 * Over SFTP: SftpRangeFetcher, on readAheadConnections new connections of its own (built with the
+	 * reconnect function), so the storage's connection stays free for other requests. Over S3:
+	 * S3_READ_AHEAD ranges at a time through the S3 client (s3ReadAhead()). Elsewhere not (yet):
+	 * null.
+	 */
+	public function canReadAhead(): bool {
+		return ($this->sftpReads && $this->reconnect !== null) || $this->s3Reads || $this->smbNative();
+	}
+
+	private function smbNative(): bool {
+		return $this->storage instanceof \OCA\Files_External\Lib\Storage\SMB && extension_loaded('smbclient');
+	}
+
+	public function readAhead(array $ranges, string $spool): ?\Generator {
+		if ($ranges !== [] && $this->s3Reads) {
+			return $this->s3ReadAhead($ranges, $spool);
+		}
+		if ($ranges !== [] && $this->smbNative()) {
+			return $this->smbReadAhead($ranges, $spool);
+		}
+		$reconnect = $this->reconnect;
+		if (!$this->sftpReads || $reconnect === null || $ranges === []) {
+			return null;
+		}
+		// before any connection is opened: an invalid path throws
+		$abs = array_map(fn (array $r): array => [$this->abs($r[0]), $r[1], $r[2]], $ranges);
+		$storages = [];
+		$connections = [];
+		$root = '';
+		$wanted = max(1, min(SftpRangeFetcher::MAX_CONNECTIONS, $this->readAheadConnections));
+		for ($n = 0; $n < $wanted; $n++) {
+			try {
+				$storage = $reconnect();
+				$sftp = SftpReadStream::connection($storage);
+				if ($sftp === null || !is_callable([$storage, 'getRoot'])) {
+					break;
+				}
+				$root = (string)$storage->getRoot();
+			} catch (\Throwable) {
+				break; // the server may allow fewer connections: go on with those that work
+			}
+			$storages[] = $storage;
+			$connections[] = $sftp;
+		}
+		if ($connections === []) {
+			return null;
+		}
+		// in place of a connection that broke: a new storage, kept like the others
+		$connect = static function () use ($reconnect, &$storages): ?object {
+			$storage = $reconnect();
+			$sftp = SftpReadStream::connection($storage);
+			if ($sftp !== null) {
+				$storages[] = $storage;
+			}
+			return $sftp;
+		};
+		return (static function () use (&$storages, $connections, $root, $abs, $spool, $connect): \Generator {
+			// the storages hold their connections: kept until the fetcher is done
+			try {
+				yield from SftpRangeFetcher::fetch($connections, $root, $abs, $spool, $connect);
+			} finally {
+				unset($storages);
+			}
+		})();
+	}
+
 	public function getRange(string $path, int $offset, int $length): string {
+		return $this->call(fn () => $this->readRange($path, $offset, $length));
+	}
+
+	private function readRange(string $path, int $offset, int $length): string {
+		try {
+			$chunks = $this->smbChunks($this->abs($path), $offset, $length);
+			if ($chunks !== null) {
+				$data = implode('', iterator_to_array($chunks, false));
+				if (strlen($data) === $length) {
+					return $data;
+				}
+			}
+		} catch (\Throwable) {
+			// read the usual way below, which reports what is wrong, over a new connection
+			$this->smbReconnect();
+		}
 		$fh = $this->get($path);
 		try {
 			if (fseek($fh, $offset) !== 0) {
@@ -99,23 +437,40 @@ final class StorageBackend implements IBackend {
 		}
 	}
 
+	/** Whether the storage accepts the connection settings (files_external's own check). */
+	public function canConnect(): bool {
+		try {
+			return !method_exists($this->storage, 'test') || $this->storage->test();
+		} catch (\Throwable) {
+			return false;
+		}
+	}
+
 	public function exists(string $path): bool {
-		return $this->storage->file_exists($this->abs($path));
+		$abs = $this->abs($path);
+		return $this->call(fn () => $this->storage->file_exists($abs), fn (bool $found) => !$found);
 	}
 
 	public function list(string $prefix): array {
-		$result = [];
-		$this->listInto($this->abs($prefix), $result);
+		$abs = $this->abs($prefix);
+		$result = $this->call(function () use ($abs): array {
+			$result = [];
+			$this->listInto($abs, $result);
+			return $result;
+		}, fn (array $found) => $found === []);
 		sort($result);
 		$cut = $this->base === '' ? 0 : strlen($this->base) + 1;
 		return array_map(fn ($p) => substr($p, $cut), $result);
 	}
 
 	public function delete(string $path): void {
+		$this->idleCheck();
 		$this->storage->unlink($this->abs($path));
 	}
 
 	public function move(string $from, string $to): void {
+		// not repeated on a new connection: the server may have done it before the connection died
+		$this->idleCheck();
 		$target = $this->abs($to);
 		$this->mkdirs(dirname($target));
 		if (!$this->storage->rename($this->abs($from), $target)) {
@@ -123,6 +478,386 @@ final class StorageBackend implements IBackend {
 		}
 	}
 
+	public function listFiles(string $dir): array {
+		$abs = $this->abs($dir);
+		return $this->call(fn () => $this->filesIn($dir, $abs), fn (array $found) => $found === []);
+	}
+
+	/** @return list<string> */
+	private function filesIn(string $dir, string $abs): array {
+		if (!$this->storage->is_dir($abs)) {
+			return []; // not created yet
+		}
+		$cut = $this->base === '' ? 0 : strlen($this->base) + 1;
+		$names = $this->smbNames($abs);
+		if ($names !== null) {
+			$result = [];
+			foreach ($names as $name) {
+				if (!self::isTemporary($name)) {
+					$result[] = substr($abs . '/' . $name, $cut);
+				}
+			}
+			sort($result);
+			return $result;
+		}
+		$dh = $this->storage->opendir($abs);
+		if ($dh === false) {
+			// An existing folder read as empty would look like a new repository.
+			throw new BackendException('Cannot list ' . $dir);
+		}
+		$result = [];
+		while (($name = readdir($dh)) !== false) {
+			if ($name !== '.' && $name !== '..' && !self::isTemporary($name)) {
+				$result[] = substr($abs . '/' . $name, $cut);
+			}
+		}
+		closedir($dh);
+		sort($result);
+		return $result;
+	}
+
+	/**
+	 * The names in an SMB folder, read in one listing; null for other storages, with access
+	 * control lists on, or when the storage's internals are not as expected. The SMB storage's
+	 * opendir() asks the server for the attributes of each entry to leave out hidden ones: with
+	 * thousands of index files that took minutes. Hidden entries are still left out: names
+	 * starting with a dot, and, after asking, any name a repository does not use (letters,
+	 * digits, - and _), such as desktop.ini or Thumbs.db. The repository's own files have such
+	 * names: they are not checked one by one, which was the cost.
+	 *
+	 * @return list<string>|null
+	 */
+	/**
+	 * Bytes per read over SMB (smbChunks()). libsmbclient keeps a large read in flight as many
+	 * requests at once; icewind's stream reads 1 MiB at a time. Over a line with a 130 ms round
+	 * trip: 4.5 MiB/s in 1 MiB reads, 18 MiB/s in 8 MiB reads (measured 2026-11-04, Samba in a
+	 * container behind netem). Without latency it makes no difference.
+	 */
+	public const SMB_READ = 8 * 1048576;
+
+	/**
+	 * $length bytes of $abs from $offset over SMB, SMB_READ at a time straight through the native
+	 * extension's state of files_external's SMB storage. Null when the storage is not SMB through
+	 * the extension, or its internals are not as expected (the usual way reads it then). The
+	 * generator throws when a read fails.
+	 *
+	 * @return \Generator<int, string>|null
+	 * @psalm-suppress UndefinedClass icewind/smb comes with files_external, not with this app
+	 */
+	private function smbChunks(string $abs, int $offset, int $length): ?\Generator {
+		$handle = $this->smbHandle($abs);
+		if ($handle === null) {
+			return null;
+		}
+		[$state, $url] = $handle;
+		/** @psalm-suppress MixedMethodCall the state is icewind's NativeState */
+		return (static function () use ($state, $url, $offset, $length): \Generator {
+			$fh = $state->open($url, 'r');
+			try {
+				$state->lseek($fh, $offset, SEEK_SET, $url);
+				for ($got = 0; $got < $length;) {
+					$want = min(self::SMB_READ, $length - $got);
+					$chunk = self::smbRead($state, $fh, $want, $url);
+					if ($chunk === '') {
+						throw new BackendException('Short read in ' . $url);
+					}
+					$got += strlen($chunk);
+					yield $chunk;
+				}
+			} finally {
+				$state->close($fh, $url);
+			}
+		})();
+	}
+
+	/**
+	 * A whole (small) file over SMB in four round trips: open, read, read up to the end, close.
+	 * files_external's fopen() first checks that the file exists (a stat with its attributes) and
+	 * icewind's stream reads 1 MiB at a time: about 7 round trips, 1 s per index file from Canada
+	 * to the Storage Box (130 ms), so ~8 h for the 27,000 index files of a 1 TB repository. Null
+	 * when the storage is not SMB through the extension or anything fails: the usual way then
+	 * reads the file and reports a missing one as such.
+	 *
+	 * @psalm-suppress UndefinedClass icewind/smb comes with files_external, not with this app
+	 */
+	private function smbWhole(string $abs): ?string {
+		$handle = $this->smbHandle($abs);
+		if ($handle === null) {
+			return null;
+		}
+		[$state, $url] = $handle;
+		try {
+			/** @psalm-suppress MixedMethodCall the state is icewind's NativeState */
+			$fh = $state->open($url, 'r');
+		} catch (\Throwable) {
+			return null;
+		}
+		$data = '';
+		try {
+			do {
+				$chunk = self::smbRead($state, $fh, self::SMB_READ, $url);
+				$data .= $chunk;
+			} while ($chunk !== '');
+		} catch (\Throwable) {
+			$data = null;
+		}
+		try {
+			/** @psalm-suppress MixedMethodCall */
+			$state->close($fh, $url);
+		} catch (\Throwable) {
+		}
+		if ($data === null) {
+			$this->smbReconnect(); // a read failed: the usual way reads it over a new connection
+		}
+		return $data;
+	}
+
+	/**
+	 * One read of at most $bytes through the native state, checked. When libsmbclient fails a read
+	 * (seen when the connection to the server dropped during a long restore), the smbclient
+	 * extension does not return false but a string whose length is -1, because it stores
+	 * smbc_read()'s -1 in an unsigned length; icewind passes it on. Counting that as data made
+	 * the read loop go backwards forever at 100% CPU (DR test 2026-11-05, after 392 GiB).
+	 *
+	 * @param resource $fh
+	 * @psalm-suppress MixedMethodCall, MixedArgument the state is icewind's NativeState
+	 */
+	private static function smbRead(object $state, $fh, int $bytes, string $url): string {
+		$chunk = $state->read($fh, $bytes, $url);
+		$n = is_string($chunk) ? strlen($chunk) : -1;
+		if ($n < 0 || $n > $bytes) {
+			throw new BackendException('Read failed in ' . $url);
+		}
+		return $chunk;
+	}
+
+	/**
+	 * After a failed read: drop icewind's connection state, so the next read (the usual way, or
+	 * the next range) connects again instead of failing on a connection that is gone.
+	 *
+	 * @psalm-suppress UndefinedClass icewind/smb comes with files_external, not with this app
+	 */
+	private function smbReconnect(): void {
+		if (!$this->storage instanceof \OCA\Files_External\Lib\Storage\SMB) {
+			return;
+		}
+		try {
+			(function (): void {
+				/** @psalm-suppress UndefinedThisPropertyFetch */
+				$share = $this->share;
+				if ($share instanceof \Icewind\SMB\Native\NativeShare) {
+					(function (): void {
+						/** @psalm-suppress UndefinedThisPropertyAssignment */
+						$this->state = null;
+					})->call($share);
+				}
+			})->call($this->storage);
+		} catch (\Throwable) {
+		}
+	}
+
+	/**
+	 * icewind's NativeState and the smb:// URL of $abs behind files_external's SMB storage, reached
+	 * through bound closures; null when the storage is not SMB through the native extension or its
+	 * internals are not as expected.
+	 *
+	 * @return array{0: object, 1: string}|null
+	 * @psalm-suppress UndefinedClass icewind/smb comes with files_external, not with this app
+	 */
+	private function smbHandle(string $abs): ?array {
+		if (!$this->storage instanceof \OCA\Files_External\Lib\Storage\SMB || !extension_loaded('smbclient')) {
+			return null;
+		}
+		try {
+			/** @var array{0: object, 1: string}|null $handle */
+			$handle = (function (string $path): ?array {
+				/** @psalm-suppress UndefinedThisPropertyFetch */
+				$share = $this->share;
+				if (!$share instanceof \Icewind\SMB\Native\NativeShare) {
+					return null;
+				}
+				/** @psalm-suppress UndefinedMethod */
+				$sharePath = ltrim($this->buildPath($path), '/');
+				/** @psalm-suppress UndefinedMethod */
+				return (fn (string $p): array => [$this->getState(), $this->buildUrl($p)])->call($share, $sharePath);
+			})->call($this->storage, $abs);
+		} catch (\Throwable) {
+			return null;
+		}
+		return $handle;
+	}
+
+	/**
+	 * readAhead() over SMB: one range after the other, each in SMB_READ reads into a file in the
+	 * spool. Not several at once (PHP cannot wait on more than one libsmbclient call), but whole
+	 * ranges of up to ReadAheadPlan::MAX_RANGE in large reads instead of blob by blob in 1 MiB
+	 * reads. A range that cannot be read is handed out as null.
+	 *
+	 * @param list<array{0:string, 1:int, 2:int}> $ranges
+	 * @return \Generator<int, resource|null>
+	 */
+	private function smbReadAhead(array $ranges, string $spool): \Generator {
+		// before anything is read: an invalid path throws
+		$abs = array_map(fn (array $r): array => [$this->abs($r[0]), $r[1], $r[2]], $ranges);
+		return (function () use ($abs, $spool): \Generator {
+			$file = rtrim($spool, '/') . '/smb-' . bin2hex(random_bytes(4));
+			try {
+				foreach ($abs as $i => [$path, $offset, $length]) {
+					$fh = null;
+					$out = false;
+					try {
+						$chunks = $this->smbChunks($path, $offset, $length);
+						$out = $chunks === null ? false : fopen($file, 'w+b');
+						if ($chunks !== null && $out !== false) {
+							foreach ($chunks as $chunk) {
+								if (fwrite($out, $chunk) !== strlen($chunk)) {
+									throw new BackendException('Cannot write to the spool');
+								}
+							}
+							$fh = ftell($out) === $length && rewind($out) ? $out : null;
+							if ($fh === null) {
+								fclose($out);
+							}
+						}
+					} catch (\Throwable) {
+						if (is_resource($out)) {
+							fclose($out);
+						}
+						$fh = null; // read the usual way, which reports why, over a new connection
+						$this->smbReconnect();
+					} finally {
+						@unlink($file); // an open stream keeps its data
+					}
+					yield $i => $fh;
+					if (is_resource($fh)) {
+						fclose($fh);
+					}
+				}
+			} finally {
+				@unlink($file);
+			}
+		})();
+	}
+
+	private function smbNames(string $abs): ?array {
+		if (!$this->storage instanceof \OCA\Files_External\Lib\Storage\SMB) {
+			return null;
+		}
+		try {
+			/** @var list<string>|null */
+			return (function (string $path): ?array {
+				/** @psalm-suppress UndefinedThisPropertyFetch */
+				if ($this->checkAcl) {
+					return null;
+				}
+				$names = [];
+				/** @psalm-suppress UndefinedThisPropertyFetch, UndefinedMethod */
+				foreach ($this->share->dir(ltrim($this->buildPath($path), '/')) as $info) {
+					$name = (string)$info->getName();
+					/** @psalm-suppress UndefinedThisPropertyFetch */
+					if (!$this->showHidden && (str_starts_with($name, '.')
+						|| (preg_match('/^[A-Za-z0-9_-]+$/', $name) !== 1 && $info->isHidden()))) {
+						continue;
+					}
+					$names[] = $name;
+				}
+				return $names;
+			})->call($this->storage, $abs);
+		} catch (\Throwable) {
+			return null; // another SMB storage version, or an error: the usual way reports it
+		}
+	}
+
+	/**
+	 * Run $op; when it throws, or $failed says its result may come from a dead connection, and
+	 * the SFTP connection turns out to be dead, run it once more on a new connection.
+	 *
+	 * @template T
+	 * @param \Closure():T $op
+	 * @param (\Closure(T):bool)|null $failed
+	 * @return T
+	 */
+	private function call(\Closure $op, ?\Closure $failed = null): mixed {
+		$this->idleCheck();
+		try {
+			$result = $op();
+		} catch (\Throwable $e) {
+			if (!$this->reopenIfDead()) {
+				throw $e;
+			}
+			return $op();
+		}
+		if ($failed !== null && $failed($result) && $this->reopenIfDead()) {
+			return $op();
+		}
+		return $result;
+	}
+
+	/**
+	 * A Hetzner Storage Box drops an SFTP connection that carried a lot of data and then stayed
+	 * quiet for a few minutes, while phpseclib still takes it for open; files_external never
+	 * builds a new one, and every request on it fails as if the file were missing. So after
+	 * such a pause the connection is checked (one round trip) before it is used again.
+	 */
+	private function idleCheck(): void {
+		$now = microtime(true);
+		if ($this->reconnect !== null && $this->sftpReads && $now - $this->lastUsed >= self::IDLE_CHECK
+			&& $this->alive(true) === false) {
+			$this->reopen();
+		}
+		$this->lastUsed = microtime(true);
+	}
+
+	/** After a failed request: ask the server (one round trip), as phpseclib may not know it is gone. */
+	private function reopenIfDead(): bool {
+		if ($this->reconnect === null || !$this->sftpReads || $this->alive(true) !== false) {
+			return false;
+		}
+		$this->reopen();
+		return true;
+	}
+
+	/**
+	 * Whether the storage's SFTP connection is alive; null when it cannot tell.
+	 * $ask: send a request instead of trusting what phpseclib saw last.
+	 */
+	private function alive(bool $ask): ?bool {
+		try {
+			if (!is_callable([$this->storage, 'getConnection'])) {
+				return null;
+			}
+			$sftp = $this->storage->getConnection();
+			if (!is_object($sftp) || !is_callable([$sftp, 'isConnected'])) {
+				return null;
+			}
+			if (!$sftp->isConnected()) {
+				return false;
+			}
+			if (!$ask || !is_callable([$sftp, 'stat'])) {
+				return true;
+			}
+			if (is_callable([$sftp, 'clearStatCache'])) {
+				$sftp->clearStatCache(); // or stat() answers from memory
+			}
+			// A Storage Box drops a quiet connection without phpseclib noticing: it still says
+			// connected, and every request fails. So the answer counts, not what it says after.
+			return $sftp->stat('.') !== false && (bool)$sftp->isConnected();
+		} catch (\Throwable) {
+			return false;
+		}
+	}
+
+	private function reopen(): void {
+		/** @var \Closure():IStorage $reconnect */
+		$reconnect = $this->reconnect;
+		$this->storage = $reconnect();
+		$this->reconnects++;
+		$this->lastUsed = microtime(true);
+		if (function_exists('OCP\Log\logger')) {
+			\OCP\Log\logger('ng_backup')->info('The SFTP connection to the backup location was lost; reconnected');
+		}
+	}
+
 	private function listInto(string $dir, array &$result): void {
 		if (!$this->storage->is_dir($dir)) {
 			return;
@@ -132,19 +867,39 @@ final class StorageBackend implements IBackend {
 			return;
 		}
 		while (($name = readdir($dh)) !== false) {
-			if ($name === '.' || $name === '..' || str_contains($name, '.part-')) {
+			if ($name === '.' || $name === '..') {
 				continue;
 			}
 			$child = $dir . '/' . $name;
 			if ($this->storage->is_dir($child)) {
 				$this->listInto($child, $result);
-			} else {
+			} elseif (!self::isTemporary($name)) {
 				$result[] = $child;
 			}
 		}
 		closedir($dh);
 	}
 
+	/**
+	 * Bytes left to read in a local $stream (php://temp, php://memory or a plain file), or null:
+	 * stream wrappers of remote storages do not report a reliable size.
+	 */
+	public static function remaining(mixed $stream): ?int {
+		if (!is_resource($stream)) {
+			return null;
+		}
+		$meta = stream_get_meta_data($stream);
+		if (!($meta['seekable'] ?? false) || !in_array($meta['wrapper_type'] ?? '', ['PHP', 'plainfile'], true)) {
+			return null;
+		}
+		$stat = fstat($stream);
+		$pos = ftell($stream);
+		if ($stat === false || $pos === false) {
+			return null;
+		}
+		return max(0, $stat['size'] - $pos);
+	}
+
 	private function mkdirs(string $dir): void {
 		if ($dir === '' || $dir === '.' || $this->storage->is_dir($dir)) {
 			return;

lib/BackgroundJob/BackupJob.php

@@ -32,19 +32,30 @@ final class BackupJob extends TimedJob {
 		private RunMapper $runs,
 		private IAppConfig $appConfig,
 		private LoggerInterface $logger,
+		private \OCA\NgBackup\Service\Schedule $schedule,
 	) {
 		parent::__construct($time);
-		$this->setInterval(300);
+		// Well below the usual 5-minute cron interval: the last run is stamped a moment after cron
+		// starts, so with 300 the next cron run came a few seconds too early and the job ran only
+		// every other time, idle for 6 of every 10 minutes during a backup. When nothing runs, the
+		// job only does a few cheap database checks.
+		$this->setInterval(60);
 		$this->setTimeSensitivity(IJob::TIME_SENSITIVE);
 	}
 
+	private const MAX_DAILY_ATTEMPTS = 3;
+
 	protected function run($argument): void {
 		$budget = PHP_SAPI === 'cli' ? 240.0 : 20.0;
 		$deadline = microtime(true) + $budget;
 		$this->startScheduled();
 		foreach ($this->runs->findRunning(null, BackupService::KIND_FULL) as $run) {
 			while (microtime(true) < $deadline && $run->getStatus() === 'running') {
-				$run = $this->backups->step($run, min($deadline, microtime(true) + $budget));
+				$next = $this->backups->step($run, min($deadline, microtime(true) + $budget));
+				if ($next === $run) {
+					break; // step() hands back the same object when another process holds the run's lease
+				}
+				$run = $next;
 			}
 		}
 		$this->failStaleRestores();
@@ -67,10 +78,15 @@ final class BackupJob extends TimedJob {
 		}
 	}
 
-	/** Once a week (after Sunday's backup), apply the retention policy to non-append-only locations. */
+	/**
+	 * Once a week, apply the retention policy to non-append-only locations: from Sunday on, at the
+	 * first moment no backup is running, so a long Sunday backup only delays it instead of skipping
+	 * the week.
+	 */
 	private function weeklyPrune(): void {
 		$lastWeek = $this->appConfig->getValueString(Application::APP_ID, 'last_prune_week', '');
-		if (date('N') !== '7' || $lastWeek === date('o-W') || $this->runs->findRunning(null, BackupService::KIND_FULL) !== []) {
+		$due = date('N') === '7' ? date('o-W') : date('o-W', (int)strtotime('last sunday'));
+		if (strcmp($lastWeek, $due) >= 0 || $this->runs->findRunning(null, BackupService::KIND_FULL) !== []) {
 			return;
 		}
 		foreach ($this->targets->list() as $t) {
@@ -83,17 +99,13 @@ final class BackupJob extends TimedJob {
 				$this->logger->warning('NG Backup: cleanup of ' . $t->getName() . ' failed: ' . $e->getMessage());
 			}
 		}
-		$this->appConfig->setValueString(Application::APP_ID, 'last_prune_week', date('o-W'));
+		$this->appConfig->setValueString(Application::APP_ID, 'last_prune_week', $due);
 	}
 
-	/** Daily schedule: appconfig ng_backup/schedule_time "HH:MM" (server time); empty = no schedule. */
+	/** Daily schedule: "HH:MM" in the schedule's time zone (see Schedule); empty = no schedule. */
 	private function startScheduled(): void {
-		$at = $this->appConfig->getValueString(Application::APP_ID, 'schedule_time', '');
-		if (!preg_match('/^([01]\d|2[0-3]):[0-5]\d$/', $at)) {
-			return;
-		}
-		$todayAt = strtotime(date('Y-m-d') . ' ' . $at);
-		if (time() < $todayAt) {
+		$todayAt = $this->schedule->todayAt();
+		if ($todayAt === null || time() < $todayAt) {
 			return;
 		}
 		foreach ($this->targets->list() as $t) {
@@ -101,6 +113,12 @@ final class BackupJob extends TimedJob {
 			if ($this->runs->findRunning($t->getId(), BackupService::KIND_FULL) !== [] || ($last !== null && $last->getStartedAt() >= $todayAt)) {
 				continue;
 			}
+			// After a failure: retry at most MAX_DAILY_ATTEMPTS times a day, an hour apart, instead
+			// of starting (and notifying about) a new full run every five minutes all day.
+			$today = $this->runs->startedSince($t->getId(), BackupService::KIND_FULL, $todayAt);
+			if (count($today) >= self::MAX_DAILY_ATTEMPTS || ($today !== [] && time() - (int)$today[0]->getFinishedAt() < 3600)) {
+				continue;
+			}
 			try {
 				$this->backups->start($t, 'scheduled');
 			} catch (\Throwable $e) {

lib/Command/BackupUser.php

@@ -0,0 +1,64 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\Command;
+
+use OCA\NgBackup\Service\TargetService;
+use OCA\NgBackup\Service\UserBackupService;
+use OCA\NgBackup\UserMigration\UserMigrationInstaller;
+use OCP\IUserManager;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputArgument;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Input\InputOption;
+use Symfony\Component\Console\Output\OutputInterface;
+
+final class BackupUser extends Command {
+	public function __construct(
+		private TargetService $targets,
+		private UserBackupService $userBackup,
+		private IUserManager $userManager,
+		private UserMigrationInstaller $installer,
+	) {
+		parent::__construct();
+	}
+
+	protected function configure(): void {
+		$this->setName('backup:user:backup')
+			->setDescription('Back up one user via user_migration (account, settings, files and everything else a migrator covers)')
+			->addArgument('target', InputArgument::REQUIRED, 'Location name or id')
+			->addArgument('user', InputArgument::REQUIRED, 'User id')
+			->addOption('install-user-migration', null, InputOption::VALUE_NONE, 'Install and enable user_migration if it is missing (non-interactive consent)')
+			->setHelp(<<<'HELP'
+Streams a user_migration export straight into the encrypted repository: no zip, no copy in the
+user's own storage. Shares data with the regular backup; this needs the user_migration app
+enabled. The manifest path this prints is what occ backup:user:restore expects.
+
+Example:
+  occ backup:user:backup offsite alice
+HELP);
+	}
+
+	protected function execute(InputInterface $input, OutputInterface $output): int {
+		$uid = (string)$input->getArgument('user');
+		$user = $this->userManager->get($uid);
+		if ($user === null) {
+			$output->writeln("<error>No such user: $uid</error>");
+			return 1;
+		}
+		try {
+			$target = $this->targets->get($input->getArgument('target'));
+			$this->installer->ensureEnabled($input, $output);
+			$manifest = $this->userBackup->backupUser($target, $user);
+		} catch (\Throwable $e) {
+			$output->writeln('<error>' . $e->getMessage() . '</error>');
+			return 1;
+		}
+		$output->writeln("Backed up <info>$uid</info> to $manifest.");
+		return 0;
+	}
+}

lib/Command/Browse.php

@@ -7,7 +7,9 @@ declare(strict_types=1);
 
 namespace OCA\NgBackup\Command;
 
+use OCA\NgBackup\Format;
 use OCA\NgBackup\Service\RestoreService;
+use OCA\NgBackup\Service\Schedule;
 use OCA\NgBackup\Service\TargetService;
 use Symfony\Component\Console\Command\Command;
 use Symfony\Component\Console\Helper\Table;
@@ -19,6 +21,7 @@ final class Browse extends Command {
 	public function __construct(
 		private TargetService $targets,
 		private RestoreService $restore,
+		private Schedule $schedule,
 	) {
 		parent::__construct();
 	}
@@ -43,9 +46,10 @@ final class Browse extends Command {
 			$output->writeln('Nothing here.');
 			return 0;
 		}
+		$zone = $this->schedule->get()['timezone'];
 		$rows = array_map(fn ($i) => [$i['type'] === 'dir' ? $i['name'] . '/' : $i['name'], $this->size($i['size']),
-			$i['type'] === 'dir' ? $i['files'] . ' files' : date('Y-m-d H:i', (int)$i['mtime'])], $items);
-		(new Table($output))->setHeaders(['name', 'size', 'files / modified'])->setRows($rows)->render();
+			$i['type'] === 'dir' ? $i['files'] . ' files' : Format::time((int)$i['mtime'], $zone)], $items);
+		(new Table($output))->setHeaders(['name', 'size', "files / modified ($zone)"])->setRows($rows)->render();
 		return 0;
 	}
 

lib/Command/CancelRun.php

@@ -0,0 +1,74 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\Command;
+
+use OCA\NgBackup\Db\Run;
+use OCA\NgBackup\Db\RunMapper;
+use OCA\NgBackup\Service\BackupService;
+use OCP\AppFramework\Db\DoesNotExistException;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputArgument;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+
+final class CancelRun extends Command {
+	public function __construct(
+		private RunMapper $runs,
+		private BackupService $backups,
+	) {
+		parent::__construct();
+	}
+
+	protected function configure(): void {
+		$this->setName('backup:cancel')
+			->setDescription('Stop a running backup')
+			->addArgument('run', InputArgument::REQUIRED, 'Run number, as shown by backup:status')
+			->setHelp("No new step of the run starts; the step in progress finishes first (usually within a
+"
+				. "minute), so a backup that is just being completed is not cut off. The process working on the
+"
+				. "run (occ backup:run, or cron) then stops. A backup started by an earlier version is marked
+"
+				. "cancelled after two minutes and stops at the end of its step. What it already stored is
+"
+				. "removed by the next cleanup.");
+	}
+
+	protected function execute(InputInterface $input, OutputInterface $output): int {
+		$id = (string)$input->getArgument('run');
+		if (!ctype_digit($id)) {
+			$output->writeln('<error>Give the run number, as shown by backup:status.</error>');
+			return 1;
+		}
+		try {
+			$run = $this->runs->find((int)$id);
+		} catch (DoesNotExistException) {
+			$output->writeln("<error>There is no run $id.</error>");
+			return 1;
+		}
+		if ($run->getKind() !== BackupService::KIND_FULL) {
+			$output->writeln("<error>Run $id is not a backup; only backups can be cancelled.</error>");
+			return 1;
+		}
+		if ($run->getStatus() === Run::RUNNING) {
+			$output->writeln("Waiting for the current step of run $id to finish...");
+		}
+		try {
+			$run = $this->backups->cancel($run);
+		} catch (\RuntimeException $e) {
+			$output->writeln('<error>' . $e->getMessage() . '</error>');
+			return 1;
+		}
+		if ($run->getStatus() !== Run::CANCELLED) {
+			$output->writeln("Run $id is not running (status: {$run->getStatus()}); nothing to cancel.");
+			return 0;
+		}
+		$output->writeln("Run $id is cancelled.");
+		return 0;
+	}
+}

lib/Command/KeyImport.php

@@ -0,0 +1,85 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\Command;
+
+use OCA\NgBackup\Service\KeyService;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputArgument;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Input\InputOption;
+use Symfony\Component\Console\Output\OutputInterface;
+use Symfony\Component\Console\Question\Question;
+
+final class KeyImport extends Command {
+	public function __construct(
+		private KeyService $keys,
+	) {
+		parent::__construct();
+	}
+
+	protected function configure(): void {
+		$this->setName('backup:key:import')
+			->setDescription('Disaster recovery: adopt the backup key from a recovery kit on a fresh installation')
+			->addArgument('kit-file', InputArgument::REQUIRED, 'The recovery kit file (occ backup:key:kit on the original installation)')
+			->addOption('passphrase-file', null, InputOption::VALUE_REQUIRED, 'Read the passphrase from this file instead of asking')
+			->setHelp(<<<'HELP'
+For a fresh installation only (occ backup:key:init must not have been run here yet). Reads one
+of the kit's passphrase slots to recover the original master key, so occ backup:target:add opens
+the existing repository on the location instead of creating a new, empty one.
+
+Example:
+  occ backup:key:import /root/ng_backup-recovery-kit.json
+  occ backup:target:add offsite sftp -a password::password -o host=... -o user=... -o password=...
+  occ backup:restore:full offsite <snapshot>
+HELP);
+	}
+
+	protected function execute(InputInterface $input, OutputInterface $output): int {
+		if ($this->keys->isInitialized()) {
+			$output->writeln('<error>A backup key already exists here (fingerprint ' . $this->keys->fingerprint() . '). occ backup:key:import is only for a fresh installation.</error>');
+			return 1;
+		}
+		$kitFile = (string)$input->getArgument('kit-file');
+		$raw = @file_get_contents($kitFile);
+		if ($raw === false) {
+			$output->writeln("<error>Cannot read $kitFile</error>");
+			return 1;
+		}
+		try {
+			$kit = json_decode($raw, true, 512, JSON_THROW_ON_ERROR);
+		} catch (\JsonException $e) {
+			$output->writeln('<error>Not a valid recovery kit file: ' . $e->getMessage() . '</error>');
+			return 1;
+		}
+		$file = $input->getOption('passphrase-file');
+		if ($file !== null) {
+			$raw = @file_get_contents($file);
+			if ($raw === false) {
+				$output->writeln('<error>Cannot read the passphrase file</error>');
+				return 1;
+			}
+			$pass = rtrim($raw, "\r\n");
+		} else {
+			$helper = $this->getHelper('question');
+			$q = (new Question('Passphrase of one of the kit\'s slots: '))->setHidden(true)->setHiddenFallback(false);
+			$pass = (string)$helper->ask($input, $output, $q);
+		}
+		try {
+			$this->keys->importRecoveryKit($kit, $pass);
+		} catch (\Throwable $e) {
+			$output->writeln('<error>' . $e->getMessage() . '</error>');
+			return 1;
+		}
+		$output->writeln('Backup key imported, fingerprint <info>' . $this->keys->fingerprint() . '</info>.');
+		// Read from the kit file, which is not authenticated beyond the wrapped key: show it so a
+		// wrong or altered value stands out.
+		$output->writeln('Deletion delay for forgotten snapshots: <info>' . $this->keys->deleteDelayDays() . '</info> days (from the kit).');
+		$output->writeln('Next: connect the backup location with the same details as before (<info>occ backup:target:add</info>), then <info>occ backup:list</info> and <info>occ backup:restore:full</info>.');
+		return 0;
+	}
+}

lib/Command/KeyInit.php

@@ -50,7 +50,7 @@ HELP);
 			$pass = rtrim((string)@file_get_contents($file), "\r\n");
 		} else {
 			$helper = $this->getHelper('question');
-			$q = (new Question('Passphrase (min. 12 characters): '))->setHidden(true)->setHiddenFallback(false);
+			$q = (new Question('Passphrase (min. ' . \OCA\NgBackup\Service\KeyService::MIN_PASSPHRASE . ' characters): '))->setHidden(true)->setHiddenFallback(false);
 			$pass = (string)$helper->ask($input, $output, $q);
 			$again = (string)$helper->ask($input, $output, (new Question('Repeat passphrase: '))->setHidden(true)->setHiddenFallback(false));
 			if ($pass !== $again) {

lib/Command/KeyKit.php

@@ -39,11 +39,24 @@ final class KeyKit extends Command {
 			$output->write($json, false, OutputInterface::OUTPUT_RAW);
 			return 0;
 		}
-		if (file_put_contents($file, $json) === false) {
+		// Created owner-only from the start (no window where it is world-readable), never over an
+		// existing file or symlink someone else may have placed at a predictable path.
+		$old = umask(0077);
+		try {
+			$fh = @fopen($file, 'xb');
+		} finally {
+			umask($old);
+		}
+		if ($fh === false) {
+			$output->writeln("<error>Cannot create $file (it must not exist yet)</error>");
+			return 1;
+		}
+		$ok = fwrite($fh, $json) === strlen($json);
+		if (!fclose($fh) || !$ok) {
+			@unlink($file);
 			$output->writeln("<error>Cannot write $file</error>");
 			return 1;
 		}
-		@chmod($file, 0600);
 		$output->writeln("Recovery kit written to <info>$file</info>. Copy it off this server, then run <info>occ backup:key:confirm</info>.");
 		return 0;
 	}

lib/Command/KeySlots.php

@@ -88,7 +88,7 @@ HELP;
 			return rtrim((string)@file_get_contents($file), "\r\n");
 		}
 		$h = $this->getHelper('question');
-		$p = (string)$h->ask($input, $output, (new Question('Passphrase (min. 12 characters): '))->setHidden(true)->setHiddenFallback(false));
+		$p = (string)$h->ask($input, $output, (new Question('Passphrase (min. ' . \OCA\NgBackup\Service\KeyService::MIN_PASSPHRASE . ' characters): '))->setHidden(true)->setHiddenFallback(false));
 		if ($p !== (string)$h->ask($input, $output, (new Question('Repeat: '))->setHidden(true)->setHiddenFallback(false))) {
 			throw new \InvalidArgumentException('The passphrases do not match');
 		}

lib/Command/ListSnapshots.php

@@ -8,6 +8,8 @@ declare(strict_types=1);
 namespace OCA\NgBackup\Command;
 
 use OCA\NgBackup\Db\SnapshotMapper;
+use OCA\NgBackup\Format;
+use OCA\NgBackup\Service\Schedule;
 use OCA\NgBackup\Service\TargetService;
 use Symfony\Component\Console\Command\Command;
 use Symfony\Component\Console\Helper\Table;
@@ -19,6 +21,7 @@ final class ListSnapshots extends Command {
 	public function __construct(
 		private TargetService $targets,
 		private SnapshotMapper $snapshots,
+		private Schedule $schedule,
 	) {
 		parent::__construct();
 	}
@@ -32,10 +35,11 @@ final class ListSnapshots extends Command {
 	protected function execute(InputInterface $input, OutputInterface $output): int {
 		$name = $input->getArgument('target');
 		$targets = $name === null ? $this->targets->list() : [$this->targets->get($name)];
+		$zone = $this->schedule->get()['timezone'];
 		$rows = [];
 		foreach ($targets as $t) {
 			foreach ($this->snapshots->findForTarget($t->getId()) as $s) {
-				$rows[] = [$t->getName(), $s->getSnapshotId(), date('Y-m-d H:i', $s->getCreatedAt()), $s->getKind(),
+				$rows[] = [$t->getName(), $s->getSnapshotId(), Format::time($s->getCreatedAt(), $zone), $s->getKind(),
 					$s->getFiles(), sprintf('%.1f GiB', ($s->getBytes() ?? 0) / 1073741824), $s->getLabel() ?? ''];
 			}
 		}
@@ -43,7 +47,7 @@ final class ListSnapshots extends Command {
 			$output->writeln('No snapshots yet (occ backup:run).');
 			return 0;
 		}
-		(new Table($output))->setHeaders(['location', 'snapshot', 'date', 'kind', 'files', 'size', 'label'])->setRows($rows)->render();
+		(new Table($output))->setHeaders(['location', 'snapshot', "date ($zone)", 'kind', 'files', 'size', 'label'])->setRows($rows)->render();
 		return 0;
 	}
 }

lib/Command/ListUserExports.php

@@ -0,0 +1,64 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\Command;
+
+use OCA\NgBackup\Service\TargetService;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Helper\Table;
+use Symfony\Component\Console\Input\InputArgument;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+
+final class ListUserExports extends Command {
+	public function __construct(
+		private TargetService $targets,
+	) {
+		parent::__construct();
+	}
+
+	protected function configure(): void {
+		$this->setName('backup:user:list')
+			->setDescription('List the user exports (backup:user:backup) on a location')
+			->addArgument('target', InputArgument::OPTIONAL, 'Location name or id (default: all)')
+			->addArgument('user', InputArgument::OPTIONAL, 'Only the exports of this user id')
+			->setHelp(<<<'HELP'
+The manifest column is what occ backup:user:restore expects. A safety export made by a restore
+with --mode=replace is listed here as well.
+
+Example:
+  occ backup:user:list offsite alice
+HELP);
+	}
+
+	protected function execute(InputInterface $input, OutputInterface $output): int {
+		$name = $input->getArgument('target');
+		$uid = $input->getArgument('user');
+		$rows = [];
+		try {
+			$targets = $name === null ? $this->targets->list() : [$this->targets->get($name)];
+			foreach ($targets as $t) {
+				foreach ($this->targets->repository($t)->listUserExports($uid) as $path) {
+					$parts = explode('/', $path, 3);
+					$user = $parts[1] ?? '';
+					$exportId = $parts[2] ?? '';
+					$time = \DateTimeImmutable::createFromFormat('Ymd\THis\Z', substr($exportId, 0, 16), new \DateTimeZone('UTC'));
+					$rows[] = [$t->getName(), $user, $time !== false ? $time->format('Y-m-d H:i') : '', $path];
+				}
+			}
+		} catch (\Throwable $e) {
+			$output->writeln('<error>' . $e->getMessage() . '</error>');
+			return 1;
+		}
+		if ($rows === []) {
+			$output->writeln('No user exports yet (occ backup:user:backup).');
+			return 0;
+		}
+		(new Table($output))->setHeaders(['location', 'user', 'date (UTC)', 'manifest'])->setRows($rows)->render();
+		return 0;
+	}
+}

lib/Command/Prune.php

@@ -37,6 +37,22 @@ final class Prune extends Command {
 		$output->writeln('Policy: ' . json_encode($this->prune->policy()->toArray()) . ($dry ? ' (dry run)' : ''));
 		$rc = 0;
 		foreach ($targets as $t) {
+			// User exports first: Repository::prune()'s blob garbage collection (run as part of
+			// apply() below) scans the users/ manifests still on the location at that point, so
+			// forgetting one here lets its now-unused blobs be freed in this same pass.
+			try {
+				$ru = $this->prune->applyUserExports($t, $dry);
+			} catch (\Throwable $e) {
+				// Snapshot retention is independent of this: report and carry on with it.
+				$output->writeln('<error>' . $t->getName() . ' (user exports): ' . $e->getMessage() . '</error>');
+				$rc = 1;
+				$ru = ['forgotten' => []];
+			}
+			if ($ru['forgotten'] !== []) {
+				$affected = count(array_unique(array_map(static fn (string $path): string => explode('/', $path)[1] ?? '', $ru['forgotten'])));
+				$output->writeln(sprintf('<info>%s</info>: %s %d user export(s) for %d user(s)',
+					$t->getName(), $dry ? 'would forget' : 'forgot', count($ru['forgotten']), $affected));
+			}
 			try {
 				$r = $this->prune->apply($t, $dry);
 			} catch (\Throwable $e) {

lib/Command/Restore.php

@@ -31,6 +31,7 @@ final class Restore extends Command {
 			->addArgument('path', InputArgument::REQUIRED, 'Path in the snapshot (see backup:browse)')
 			->addOption('mode', 'm', InputOption::VALUE_REQUIRED, 'new-folder, merge or replace (user files)', RestoreService::MODE_NEW_FOLDER)
 			->addOption('to-directory', 'd', InputOption::VALUE_REQUIRED, 'Write to this local directory instead (any path, raw files)')
+			->addOption('salvage', null, InputOption::VALUE_NONE, 'Leave out a file that cannot be read or decrypted, list it at the end and go on, instead of stopping')
 			->setHelp(<<<'HELP'
 User files (data/<user>/files/...) are restored through Nextcloud, so versions, trash and the
 file cache stay correct. Modes:
@@ -42,30 +43,59 @@ Examples:
   occ backup:restore offsite 537bf7e9... data/alice/files/Documents
   occ backup:restore offsite 537bf7e9... data/alice/files/Documents/plan.odt --mode=merge
   occ backup:restore offsite 537bf7e9... config --to-directory=/root/restored-config
+With --salvage, a file whose data on the location is damaged or missing is left out and listed
+at the end; everything else is restored. The command then exits with code 2.
 HELP);
 	}
 
 	protected function execute(InputInterface $input, OutputInterface $output): int {
+		$skipped = $input->getOption('salvage') ? [] : null;
 		try {
 			$target = $this->targets->get($input->getArgument('target'));
 			$snapshot = $input->getArgument('snapshot');
 			$path = trim((string)$input->getArgument('path'), '/'); // CLI convenience; the service itself only accepts canonical paths
 			if ($dir = $input->getOption('to-directory')) {
-				$n = $this->restore->restoreToDirectory($target, $snapshot, $path, $dir);
+				$n = $this->restore->restoreToDirectory($target, $snapshot, $path, $dir, false, null, $skipped);
 				$output->writeln("Restored <info>$n</info> files to $dir.");
-				return 0;
+				return self::reportSkipped($skipped, $output);
 			}
 			$r = $this->restore->restoreUserFiles($target, $snapshot, $path, (string)$input->getOption('mode'),
 				function (int $done, int $total, string $name) use ($output) {
 					if ($output->isVerbose() || $done === $total || $done % 100 === 0) {
 						$output->writeln("  $done/$total $name");
 					}
-				});
+				}, $skipped);
 		} catch (\Throwable $e) {
 			$output->writeln('<error>' . $e->getMessage() . '</error>');
+			if ($skipped === null && self::backupLooksDamaged($e)) {
+				$output->writeln('The data of a file on the location is damaged or missing. Run the same command with --salvage to restore everything else and list what could not be restored.');
+			}
 			return 1;
 		}
 		$output->writeln(sprintf('Restored <info>%d</info> files to %s%s.', $r['restored'], $r['target'], $r['trashed'] ? ", moved {$r['trashed']} extra files to the trash" : ''));
-		return 0;
+		return self::reportSkipped($skipped, $output);
+	}
+
+	/** Damaged data, or a file that is gone from the location: what --salvage is for. */
+	public static function backupLooksDamaged(\Throwable $e): bool {
+		return $e instanceof \OCA\NgBackup\Repository\RepositoryException
+			|| $e instanceof \OCA\NgBackup\Crypto\CryptoException
+			|| ($e instanceof \OCA\NgBackup\Backend\BackendException && str_starts_with($e->getMessage(), 'Not found'));
+	}
+
+	/**
+	 * The files --salvage left out; exit code 2 when there are any.
+	 *
+	 * @param array<string, string>|null $skipped
+	 */
+	public static function reportSkipped(?array $skipped, OutputInterface $output): int {
+		if ($skipped === null || $skipped === []) {
+			return 0;
+		}
+		$output->writeln(sprintf('<comment>%d file%s could not be restored (damaged or missing on the location):</comment>', count($skipped), count($skipped) === 1 ? '' : 's'));
+		foreach ($skipped as $path => $reason) {
+			$output->writeln("  $path: $reason");
+		}
+		return 2;
 	}
 }

lib/Command/RestoreFull.php

@@ -0,0 +1,184 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\Command;
+
+use OCA\NgBackup\Service\RestoreFullService;
+use OCA\NgBackup\Service\TargetService;
+use OCP\IUserManager;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Helper\QuestionHelper;
+use Symfony\Component\Console\Input\InputOption;
+use Symfony\Component\Console\Question\ConfirmationQuestion;
+use Symfony\Component\Console\Input\InputArgument;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+
+final class RestoreFull extends Command {
+	public function __construct(
+		private TargetService $targets,
+		private RestoreFullService $restoreFull,
+		private IUserManager $userManager,
+		private \OCP\App\IAppManager $appManager,
+	) {
+		parent::__construct();
+	}
+
+	protected function configure(): void {
+		$this->setName('backup:restore:full')
+			->setDescription('Disaster recovery: restore the database, data directory and config on a fresh installation')
+			->addArgument('target', InputArgument::REQUIRED, 'Location name or id')
+			->addArgument('snapshot', InputArgument::REQUIRED, 'Snapshot id (see backup:list)')
+			->addOption('force', null, InputOption::VALUE_NONE, 'Also on an installation that already has more than one user, and without asking')
+			->addOption('install-apps', null, InputOption::VALUE_NONE, 'First install (from the app store) or enable the apps that were enabled at backup time and are missing here')
+			->addOption('skip-missing-tables', null, InputOption::VALUE_NONE, 'Older backups only: leave out tables that do not exist here and whose structure the backup does not record')
+			->addOption('salvage', null, InputOption::VALUE_NONE, 'Restore what can be restored: leave out files that cannot be read, and when the database cannot be restored, put the files in a folder of their own')
+			->setHelp(<<<'HELP'
+For a FRESH Nextcloud installation only, same major version as the backup, right after
+occ maintenance:install, occ backup:key:import and occ backup:target:add -- before anyone else
+uses this instance.
+
+Apps: --install-apps first installs (from the app store) or enables every app that was enabled
+when the snapshot was taken. Apps that are not in the app store (own builds) must be copied into
+custom_apps by hand; the command lists what is still missing. Tables of apps that are missing or
+were removed long ago are created from the structure recorded in the backup (backups made with
+1.0.0-rc.2 or later), so they do not block the restore. Older backups do not record it: the
+command then lists those tables per app, and --skip-missing-tables leaves them out.
+
+Steps: the database is replaced (consistent, in one transaction); the data directory is restored
+directly in place; config.php is merged in -- everything from the backup except the database
+connection and data directory settings, which stay as occ maintenance:install configured them
+here. Other files under config/ (if any) are not restored.
+
+Afterwards: check trusted_domains and overwritehost/overwriteprotocol match this server, and
+occ maintenance:repair.
+When the backup is damaged: --salvage restores what can be restored. Files whose data cannot be
+read or decrypted are left out and listed. When the database cannot be restored (its dump is
+damaged, or it does not fit this installation), the database stays as occ maintenance:install
+made it, and the data directory and config of the backup go to ngb-salvage-<snapshot> in the
+data directory instead: from there, the files can be put back by hand. The command then exits
+with code 2.
+
+Example:
+  occ backup:restore:full offsite 537bf7e9c1a4...
+HELP);
+	}
+
+	protected function execute(InputInterface $input, OutputInterface $output): int {
+		$force = (bool)$input->getOption('force');
+		// A whole-server restore replaces the database and data directory of THIS instance. On
+		// anything but a fresh install (only the admin from occ maintenance:install) that is
+		// almost certainly a mistake, so it needs --force.
+		$users = $this->userManager->countUsersTotal(2);
+		if (!$force && ($users === false || $users > 1)) {
+			$output->writeln('<error>This installation already has more than one user: backup:restore:full would replace its whole database and data directory. It is meant for a fresh installation. Use --force if this really is what you want.</error>');
+			return 1;
+		}
+		if (!$force && $input->isInteractive()) {
+			$q = new ConfirmationQuestion('This replaces the database, the data directory and config.php of this installation. Continue? [y/N] ', false);
+			if (!(new QuestionHelper())->ask($input, $output, $q)) {
+				$output->writeln('Cancelled.');
+				return 1;
+			}
+		}
+		try {
+			$target = $this->targets->get($input->getArgument('target'));
+			$snapshot = (string)$input->getArgument('snapshot');
+			$skipMissingTables = (bool)$input->getOption('skip-missing-tables');
+			$salvage = (bool)$input->getOption('salvage');
+			if ($input->getOption('install-apps')) {
+				$check = $this->restoreFull->checkCompatibility($target, $snapshot, $skipMissingTables, $salvage);
+				foreach ($check['missingApps'] as $app) {
+					$this->installApp($app, $output);
+				}
+			}
+			$output->writeln('Nextcloud is in maintenance mode while the restore runs; it is switched off when the restore completes.');
+			$result = $this->restoreFull->restoreFull($target, $snapshot, $skipMissingTables, $salvage);
+		} catch (\Throwable $e) {
+			$output->writeln('<error>' . $e->getMessage() . '</error>');
+			if (\OCP\Server::get(\OCP\IConfig::class)->getSystemValueBool('maintenance', false)) {
+				$output->writeln('The restore had started: the instance may be partly restored, and maintenance mode stays on so that nobody uses it like that.');
+				$output->writeln('Fix the cause, then switch maintenance mode off and run the same command again with --force, in one line:');
+				$again = 'occ backup:restore:full ' . escapeshellarg((string)$input->getArgument('target')) . ' ' . escapeshellarg((string)$input->getArgument('snapshot'))
+					. ($input->getOption('skip-missing-tables') ? ' --skip-missing-tables' : '') . ($input->getOption('salvage') ? ' --salvage' : '') . ' --force --no-interaction';
+				$output->writeln('  occ maintenance:mode --off && ' . $again);
+				$output->writeln('(Without --install-apps, so the instance is open only for the seconds until the restore starts again. Apps the first run could not install are listed at the end: install those afterwards.)');
+			} else {
+				$output->writeln('If this happened after the restore had started, the instance may be partly restored: fix the cause and run the same command again with --force.');
+			}
+			$output->writeln('If occ then says that Nextcloud needs an upgrade (the database is already the old server\'s), run occ upgrade first.');
+			if (!$input->getOption('salvage') && Restore::backupLooksDamaged($e)) {
+				$output->writeln('The backup itself looks damaged here. --salvage restores everything that can be read and lists the rest.');
+			}
+			return 1;
+		}
+		if ($result['dbError'] !== null) {
+			$output->writeln('<error>Salvage: ' . $result['dbError'] . '</error>');
+			$output->writeln(sprintf('The database stays as occ maintenance:install made it. The data directory and config of the backup (<info>%d</info> data files) are in:', $result['dataFiles']));
+			$output->writeln('  ' . $result['salvageDir']);
+			$output->writeln('Each user\'s files are in data/<user>/files there. Put back what is needed by hand, for example into the files of new users (then occ files:scan).');
+			Restore::reportSkipped($result['skipped'], $output);
+			return 2;
+		}
+		$output->writeln(sprintf(
+			'Database restored (<info>%d</info> tables, <info>%d</info> unchanged), config merged (<info>%d</info> keys), <info>%d</info> data files restored.',
+			count($result['dbReport']['restored']),
+			count($result['dbReport']['skipped']),
+			$result['configKeys'],
+			$result['dataFiles'],
+		));
+		if ($result['dbReport']['created'] !== []) {
+			$output->writeln(sprintf('Created <info>%d</info> tables that did not exist here (apps that are missing or were removed): %s',
+				count($result['dbReport']['created']), implode(', ', $result['dbReport']['created'])));
+		}
+		foreach ($result['dbReport']['foreignKeyErrors'] ?? [] as $error) {
+			$output->writeln('<comment>Could not add a foreign key to a created table (the data is restored): ' . $error . '</comment>');
+		}
+		if ($result['dbReport']['missing'] !== []) {
+			$output->writeln('<comment>Left out (structure unknown): ' . implode(', ', $result['dbReport']['missing']) . '</comment>');
+		}
+		if ($result['missingApps'] !== []) {
+			$output->writeln('<comment>These apps were enabled on the old server but are not installed here. Their data is restored; install them so they work again:</comment>');
+			foreach ($result['missingApps'] as $app) {
+				$output->writeln("  occ app:install $app   (not in the app store? copy it into custom_apps and run occ app:enable $app)");
+			}
+		}
+		if (!$result['dbConsistent']) {
+			$output->writeln('<comment>Warning: this snapshot\'s database dump was made over several steps (web cron), so it is not one consistent point in time. Check the instance carefully; prefer a snapshot made with system cron.</comment>');
+		}
+		if ($result['maintenanceLeftOn']) {
+			$output->writeln('<comment>Maintenance mode was on before the restore and stays on: switch it off with occ maintenance:mode --off when the instance is ready.</comment>');
+		}
+		$output->writeln('Next: check trusted_domains and overwritehost/overwriteprotocol match this server, then occ maintenance:repair.');
+		$code = 0;
+		if ($result['configError'] !== null) {
+			$output->writeln('<comment>Salvage: config.php of the backup was not merged (' . $result['configError'] . '). Set at least \'instanceid\', \'passwordsalt\' and \'secret\' to the old server\'s values if you have them, or data encrypted with them (server-side encryption, stored passwords) cannot be read.</comment>');
+			$code = 2;
+		}
+		return max($code, Restore::reportSkipped($result['skipped'], $output));
+	}
+
+	/** Enable an app that is here but switched off, or install it from the app store. */
+	private function installApp(string $app, OutputInterface $output): void {
+		try {
+			$this->appManager->getAppPath($app);
+			$command = 'app:enable'; // here, but switched off
+		} catch (\OCP\App\AppPathNotFoundException) {
+			$command = 'app:install';
+		}
+		$output->writeln("Running occ $command $app ...");
+		try {
+			$code = $this->getApplication()?->find($command)->run(new \Symfony\Component\Console\Input\ArrayInput(['app-id' => $command === 'app:enable' ? [$app] : $app]), $output);
+		} catch (\Throwable $e) {
+			$code = 1;
+			$output->writeln('<comment>' . $e->getMessage() . '</comment>');
+		}
+		if ($code !== 0) {
+			$output->writeln("<comment>Could not $command $app (not in the app store?). Copy it into custom_apps and enable it, or restore without it.</comment>");
+		}
+	}
+}

lib/Command/RestoreUser.php

@@ -0,0 +1,96 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\Command;
+
+use OCA\NgBackup\Service\TargetService;
+use OCA\NgBackup\Service\UserRestoreService;
+use OCA\NgBackup\UserMigration\UserMigrationInstaller;
+use OCP\IUserManager;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Helper\QuestionHelper;
+use Symfony\Component\Console\Question\ConfirmationQuestion;
+use Symfony\Component\Console\Input\InputArgument;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Input\InputOption;
+use Symfony\Component\Console\Output\OutputInterface;
+
+final class RestoreUser extends Command {
+	public function __construct(
+		private TargetService $targets,
+		private UserRestoreService $userRestore,
+		private UserMigrationInstaller $installer,
+		private IUserManager $userManager,
+	) {
+		parent::__construct();
+	}
+
+	protected function configure(): void {
+		$this->setName('backup:user:restore')
+			->setDescription('Restore a user from a user_migration export (see backup:user:backup)')
+			->addArgument('target', InputArgument::REQUIRED, 'Location name or id')
+			->addArgument('manifest', InputArgument::REQUIRED, 'Manifest path printed by backup:user:backup (users/<uid>/<exportId>), or a user id with exactly one export')
+			->addOption('mode', 'm', InputOption::VALUE_REQUIRED, 'replace or as-backup', UserRestoreService::MODE_REPLACE)
+			->addOption('force', null, InputOption::VALUE_NONE, 'Replace an existing account without asking (required when not interactive)')
+			->addOption('install-user-migration', null, InputOption::VALUE_NONE, 'Install and enable user_migration if it is missing (non-interactive consent)')
+			->setHelp(<<<'HELP'
+Never imports over a live account. Modes:
+  replace    (default) safety-exports the current account first, then deletes and recreates it
+             fresh from the backup, under the same user id
+  as-backup  restores into a new account "<uid>-bak" (or "-bak-2", ...) instead, so an admin can
+             compare and transfer by hand; Nextcloud cannot rename a user id, so the backup gets
+             the new name, never the existing account
+
+occ backup:user:list shows the exports on a location. A user id alone works when that user
+has exactly one export there; with more, the command lists them and you pass one.
+
+Example:
+  occ backup:user:restore offsite users/alice/20261005T120000Z-ab12cd34
+  occ backup:user:restore offsite alice
+  occ backup:user:restore offsite users/alice/20261005T120000Z-ab12cd34 --mode=as-backup
+HELP);
+	}
+
+	protected function execute(InputInterface $input, OutputInterface $output): int {
+		$mode = (string)$input->getOption('mode');
+		try {
+			$target = $this->targets->get($input->getArgument('target'));
+			$ref = (string)$input->getArgument('manifest');
+			$manifest = $this->targets->repository($target)->resolveUserExport($ref);
+		} catch (\Throwable $e) {
+			$output->writeln('<error>' . $e->getMessage() . '</error>');
+			return 1;
+		}
+		if ($manifest !== $ref) {
+			$output->writeln("Using $manifest.");
+		}
+		$uid = explode('/', $manifest)[1];
+		if ($mode === UserRestoreService::MODE_REPLACE && $this->userManager->userExists($uid) && !$input->getOption('force')) {
+			// Replace deletes the live account (after a safety export). Shares to others and data of
+			// apps without a user_migration migrator do not come back, so never do it unasked.
+			if (!$input->isInteractive()) {
+				$output->writeln("<error>$uid exists: --mode=replace deletes and recreates it. Add --force, or use --mode=as-backup.</error>");
+				return 1;
+			}
+			$q = new ConfirmationQuestion("$uid exists and will be deleted and recreated from the backup (a safety export is made first; its shares to others and data of apps without a migrator are not restored). Continue? [y/N] ", false);
+			if (!(new QuestionHelper())->ask($input, $output, $q)) {
+				$output->writeln('Cancelled.');
+				return 1;
+			}
+		}
+		try {
+			$output->writeln('<comment>Note: on restore, user_migration only imports the app settings on its own allowlist (e.g. calendar view and reminder settings); other app settings of this user are skipped. Reason: NG Backup uses user_migration\'s importer; widening the list would mean building a settings importer of our own.</comment>');
+			$this->installer->ensureEnabled($input, $output);
+			$user = $this->userRestore->restoreUser($target, $manifest, $mode);
+		} catch (\Throwable $e) {
+			$output->writeln('<error>' . $e->getMessage() . '</error>');
+			return 1;
+		}
+		$output->writeln('Restored <info>' . $user->getUID() . '</info>.');
+		return 0;
+	}
+}

lib/Command/Retention.php

@@ -28,10 +28,15 @@ final class Retention extends Command {
 			->addOption('daily', null, InputOption::VALUE_REQUIRED, 'Keep one per day for the last N days with a backup')
 			->addOption('weekly', null, InputOption::VALUE_REQUIRED, 'Keep one per week for N weeks')
 			->addOption('monthly', null, InputOption::VALUE_REQUIRED, 'Keep one per month for N months')
-			->setHelp("Example: occ backup:retention --last=3 --daily=7 --weekly=4 --monthly=12");
+			->addOption('user-last', null, InputOption::VALUE_REQUIRED, 'Keep the newest N of each user\'s own exports (occ backup:user:backup)')
+			->setHelp("Example: occ backup:retention --last=3 --daily=7 --weekly=4 --monthly=12 --user-last=3");
 	}
 
 	protected function execute(InputInterface $input, OutputInterface $output): int {
+		if ($input->getOption('user-last') !== null && !ctype_digit((string)$input->getOption('user-last'))) {
+			$output->writeln('<error>--user-last must be a whole number</error>');
+			return 1;
+		}
 		$p = $this->prune->policy()->toArray();
 		$changed = false;
 		foreach (['last', 'daily', 'weekly', 'monthly'] as $k) {
@@ -48,7 +53,16 @@ final class Retention extends Command {
 				return 1;
 			}
 		}
+		if ($input->getOption('user-last') !== null) {
+			try {
+				$this->prune->setUserExportRetention((int)$input->getOption('user-last'));
+			} catch (\InvalidArgumentException $e) {
+				$output->writeln('<error>' . $e->getMessage() . '</error>');
+				return 1;
+			}
+		}
 		$output->writeln(sprintf('Keep the last %d, plus one per day for %d days, per week for %d weeks, per month for %d months.', $p['last'], $p['daily'], $p['weekly'], $p['monthly']));
+		$output->writeln(sprintf('Keep the newest %d of each user\'s own exports.', $this->prune->userExportRetention()));
 		return 0;
 	}
 }

lib/Command/RunBackup.php

@@ -75,6 +75,13 @@ HELP);
 			});
 			if ($run->getStatus() === Run::DONE) {
 				$output->writeln(sprintf('  done in %.0fs', microtime(true) - $start));
+				$f = json_decode($run->getStats() ?? '{}', true)['files'] ?? [];
+				if (($f['unreadable'] ?? 0) > 0) {
+					$output->writeln(sprintf('<comment>  warning: %d unreadable files or folders are missing from this backup (see the server log)</comment>', $f['unreadable']));
+				}
+				if (($f['changing'] ?? 0) > 0) {
+					$output->writeln(sprintf('<comment>  warning: %d files kept changing and were saved as read (see the server log)</comment>', $f['changing']));
+				}
 			} else {
 				$output->writeln('<error>  ' . $run->getStatus() . ': ' . $run->getError() . '</error>');
 				$failed++;

lib/Command/Status.php

@@ -8,33 +8,50 @@ declare(strict_types=1);
 namespace OCA\NgBackup\Command;
 
 use OCA\NgBackup\Db\RunMapper;
+use OCA\NgBackup\Format;
+use OCA\NgBackup\Service\CronHealth;
 use OCA\NgBackup\Service\KeyService;
+use OCA\NgBackup\Service\Schedule;
 use OCA\NgBackup\Service\TargetService;
+use OCA\NgBackup\Service\VerifyService;
 use Symfony\Component\Console\Command\Command;
 use Symfony\Component\Console\Helper\Table;
 use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Input\InputOption;
 use Symfony\Component\Console\Output\OutputInterface;
 
 final class Status extends Command {
+	/** Runs of the last days that are listed by default (failed ones stay visible that long). */
+	public const RECENT_DAYS = 7;
+
 	public function __construct(
 		private KeyService $keys,
 		private TargetService $targets,
 		private RunMapper $runs,
+		private VerifyService $verify,
+		private Schedule $schedule,
+		private CronHealth $cron,
 	) {
 		parent::__construct();
 	}
 
 	protected function configure(): void {
-		$this->setName('backup:status')->setDescription('Show the backup key, locations and recent runs');
+		$this->setName('backup:status')->setDescription('Show the backup key, locations and recent runs')
+			->addOption('all', null, InputOption::VALUE_NONE, 'List all runs, not only those of the last ' . self::RECENT_DAYS . ' days');
 	}
 
 	protected function execute(InputInterface $input, OutputInterface $output): int {
+		$zone = $this->schedule->get()['timezone'];
+		$cronProblem = CronHealth::describe($this->cron->check());
+		if ($cronProblem !== null) {
+			$output->writeln('<error>' . $cronProblem . '</error>');
+		}
 		if (!$this->keys->isInitialized()) {
 			$output->writeln('Key: <error>not created</error> (occ backup:key:init)');
 		} else {
 			$c = $this->keys->recoveryKitConfirmation();
 			$output->writeln('Key: ' . $this->keys->fingerprint() . ', recovery kit '
-				. ($c ? 'confirmed by ' . $c['uid'] . ' on ' . date('Y-m-d H:i', $c['time']) : '<error>not confirmed</error> (occ backup:key:confirm)'));
+				. ($c ? 'confirmed by ' . $c['uid'] . ' on ' . Format::time($c['time'], $zone) . " ($zone)" : '<error>not confirmed</error> (occ backup:key:confirm)'));
 		}
 		$names = [];
 		foreach ($this->targets->list() as $t) {
@@ -42,15 +59,59 @@ final class Status extends Command {
 		}
 		$output->writeln('Locations: ' . ($names === [] ? 'none' : implode(', ', $names)));
 		$rows = [];
-		foreach ($this->runs->findRecent(10) as $r) {
+		$all = (bool)$input->getOption('all');
+		$shown = $this->runs->findShown($all ? null : time() - self::RECENT_DAYS * 86400);
+		foreach ($shown as $r) {
 			$s = json_decode($r->getStats() ?? '{}', true)['files'] ?? [];
-			$rows[] = [$r->getId(), $names[$r->getTargetId()] ?? '#' . $r->getTargetId(), $r->getKind(), $r->getStatus() . ($r->getStatus() === 'running' ? ' (' . $r->getPhase() . ')' : ''),
-				date('Y-m-d H:i', $r->getStartedAt()), $r->getFinishedAt() ? gmdate('H:i:s', $r->getFinishedAt() - $r->getStartedAt()) : '',
-				$s['files'] ?? '', isset($s['uploaded']) ? sprintf('%.1f MiB', $s['uploaded'] / 1048576) : '', mb_strimwidth((string)$r->getError(), 0, 50, '…')];
+			$rows[] = [$r->getId(), $names[$r->getTargetId()] ?? '#' . $r->getTargetId(), $r->getKind(), $r->getStatus() === 'running' ? self::runningStatus($r) : $r->getStatus(),
+				Format::time($r->getStartedAt(), $zone), $r->getFinishedAt() ? Format::duration($r->getFinishedAt() - $r->getStartedAt()) : '',
+				$s['files'] ?? '', isset($s['bytes']) ? self::size((int)$s['bytes']) : '',
+				isset($s['uploaded']) ? self::size((int)$s['uploaded']) : '', mb_strimwidth((string)$r->getError(), 0, 50, '…')];
 		}
 		if ($rows !== []) {
-			(new Table($output))->setHeaders(['run', 'location', 'kind', 'status', 'started', 'took', 'files', 'uploaded', 'error'])->setRows($rows)->render();
+			(new Table($output))->setHeaders(['run', 'location', 'kind', 'status', "started ($zone)", 'took', 'files', 'size', 'uploaded', 'error'])->setRows($rows)->render();
+		}
+		$older = $all ? 0 : $this->runs->countAll() - count($shown);
+		if ($older > 0) {
+			$output->writeln(sprintf('%d older run%s not shown (--all)', $older, $older === 1 ? '' : 's'));
+		}
+		foreach ($this->verify->progress() as $targetId => $state) {
+			$output->writeln(sprintf('Verify of %s on %s: %s', mb_strimwidth((string)($state['what'] ?? ''), 0, 40, '…'),
+				$names[$targetId] ?? '#' . $targetId, VerifyService::describe($state)));
 		}
 		return 0;
 	}
+
+	/** " 68%", or " ~68%" when estimated from the file cache; empty without an estimate */
+	private static function size(int $bytes): string {
+		$b = (float)$bytes;
+		foreach (['B', 'KiB', 'MiB', 'GiB'] as $u) {
+			if ($b < 1024) {
+				return $u === 'B' ? "$bytes B" : sprintf('%.1f %s', $b, $u);
+			}
+			$b /= 1024.0;
+		}
+		return sprintf('%.1f TiB', $b);
+	}
+
+	/** " 47/183 tables" in the database phase, " 68%" or " ~68%" in the files phase; empty without a figure */
+	private static function percent(\OCA\NgBackup\Db\Run $r): string {
+		$p = \OCA\NgBackup\Job\BackupRun::progressOf($r);
+		if ($p === null) {
+			return '';
+		}
+		if (isset($p['tables'], $p['totalTables'])) {
+			return sprintf(': %d/%d tables', $p['tables'], $p['totalTables']);
+		}
+		return sprintf(' %s%d%%', $p['approximate'] ? '~' : '', (int)floor($p['fraction'] * 100.0));
+	}
+
+	/** "running (db: 47/183 tables)", or "waiting for background jobs (last step 12 min ago)" */
+	private static function runningStatus(\OCA\NgBackup\Db\Run $r): string {
+		$waiting = $r->getKind() === \OCA\NgBackup\Service\BackupService::KIND_FULL ? CronHealth::waitingFor($r) : null;
+		if ($waiting !== null) {
+			return 'waiting for background jobs (' . $r->getPhase() . self::percent($r) . ', last step ' . CronHealth::ago($waiting) . ')';
+		}
+		return 'running (' . $r->getPhase() . self::percent($r) . ')';
+	}
 }

lib/Command/TargetAdd.php

@@ -44,7 +44,10 @@ HELP);
 
 	protected function execute(InputInterface $input, OutputInterface $output): int {
 		if (!$this->keys->isInitialized()) {
-			$output->writeln('<error>No backup key yet: run occ backup:key:init first.</error>');
+			$output->writeln('<error>No backup key yet.</error>');
+			$output->writeln('Restoring from a location that already has backups (disaster recovery)? Import the key from the recovery kit first:');
+			$output->writeln('  occ backup:key:import /path/to/ng_backup-kit.json');
+			$output->writeln('Only for a new location without backups: create a new key with occ backup:key:init. A new key cannot read existing backups.');
 			return 1;
 		}
 		$options = [];
@@ -60,9 +63,16 @@ HELP);
 			$output->writeln('<error>--auth is required (see occ backup:target:backends)</error>');
 			return 1;
 		}
+		// Adopting an existing repository reads its whole index first, which takes a while on a
+		// large backup or a slow line; show how far it is instead of looking stuck.
+		$output->writeln('Connecting to the location; with existing backups this reads their index first ...');
 		try {
-			$r = $this->targets->add($input->getArgument('name'), $input->getArgument('backend'), $input->getOption('auth'), $options, (string)$input->getOption('path'));
+			$r = $this->targets->add($input->getArgument('name'), $input->getArgument('backend'), $input->getOption('auth'), $options,
+				(string)$input->getOption('path'), self::progress($output));
 		} catch (\Throwable $e) {
+			if ($output->isDecorated()) {
+				$output->write("\r\033[K"); // clear an unfinished progress line
+			}
 			$output->writeln('<error>' . $e->getMessage() . '</error>');
 			return 1;
 		}
@@ -70,4 +80,49 @@ HELP);
 			$r['target']->getRepositoryId(), $r['created'] ? 'created' : 'found and adopted'));
 		return 0;
 	}
+
+	/**
+	 * Progress of reading the index: on a terminal one line that is updated in place, otherwise
+	 * (a log, a pipe) a line every 30 seconds. The time left is estimated from the rate so far.
+	 *
+	 * @return callable(int, int): void
+	 */
+	private static function progress(OutputInterface $output): callable {
+		$shown = 0.0;
+		$first = null; // [time, files done] when the first files were in
+		$inPlace = $output->isDecorated();
+		return static function (int $done, int $total) use ($output, &$shown, &$first, $inPlace): void {
+			$now = microtime(true);
+			if ($first === null && $done > 0) {
+				$first = [$now, $done];
+			}
+			if ($done < $total && $now - $shown < ($inPlace ? 1 : 30)) {
+				return;
+			}
+			$shown = $now;
+			$line = sprintf('Reading the index: %s/%s files (%d%%)', number_format($done), number_format($total), intdiv(100 * $done, max(1, $total)));
+			$left = $first === null ? null : self::minutesLeft($now - $first[0], $done - $first[1], $total - $done, $total);
+			if ($left !== null) {
+				$line .= $left <= 1 ? ', less than a minute left' : sprintf(', about %d min left', $left);
+			}
+			if ($inPlace) {
+				$output->write("\r\033[K" . $line . ($done >= $total ? "\n" : ''));
+			} else {
+				$output->writeln($line);
+			}
+		};
+	}
+
+	/**
+	 * Minutes left for reading the index, from the rate since the first files were in: the first
+	 * file also carries the time to connect, which made an S3 location with 4,568 index files
+	 * say "about 642 min left" for something done within a minute. No estimate until 5% of the
+	 * files, or 50 files, came in after that, and at least 5 seconds passed.
+	 */
+	public static function minutesLeft(float $elapsed, int $done, int $left, int $total): ?int {
+		if ($left <= 0 || $done <= 0 || $elapsed < 5.0 || ($done < 50 && $done * 20 < $total)) {
+			return null;
+		}
+		return (int)ceil($elapsed / (float)$done * (float)$left / 60.0);
+	}
 }

lib/Command/TargetEdit.php

@@ -0,0 +1,71 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\Command;
+
+use OCA\NgBackup\Service\AlertService;
+use OCA\NgBackup\Service\TargetService;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputArgument;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Input\InputOption;
+use Symfony\Component\Console\Output\OutputInterface;
+
+final class TargetEdit extends Command {
+	public function __construct(
+		private TargetService $targets,
+		private AlertService $alerts,
+	) {
+		parent::__construct();
+	}
+
+	protected function configure(): void {
+		$this->setName('backup:target:edit')
+			->setDescription('Change the connection settings or the name of a backup location, keeping its backups')
+			->addArgument('target', InputArgument::REQUIRED, 'Location name or id')
+			->addOption('name', null, InputOption::VALUE_REQUIRED, 'New name')
+			->addOption('backend', 'b', InputOption::VALUE_REQUIRED, 'New files_external backend id (see backup:target:backends)')
+			->addOption('auth', 'a', InputOption::VALUE_REQUIRED, 'New auth mechanism id')
+			->addOption('option', 'o', InputOption::VALUE_REQUIRED | InputOption::VALUE_IS_ARRAY, 'Option key=value to change (repeatable); other options keep their value')
+			->addOption('path', 'p', InputOption::VALUE_REQUIRED, 'New folder on the location')
+			->setHelp(<<<'HELP'
+The new settings must lead to the same repository as before, so the history of the location is
+kept. Use it after a password change, a new host name, or after moving the repository.
+
+Example:
+  occ backup:target:edit nas -o password=new-secret
+HELP);
+	}
+
+	protected function execute(InputInterface $input, OutputInterface $output): int {
+		try {
+			$t = $this->targets->get($input->getArgument('target'));
+			$options = $this->targets->options($t);
+			if ($input->getOption('backend') !== null || $input->getOption('auth') !== null) {
+				$options = []; // a different connection type has its own options
+			}
+			foreach ($input->getOption('option') as $pair) {
+				if (!str_contains($pair, '=')) {
+					$output->writeln("<error>Option '$pair' must be key=value</error>");
+					return 1;
+				}
+				$k = (string)strstr($pair, '=', true);
+				$v = substr($pair, strlen($k) + 1);
+				$options[$k] = match (strtolower($v)) { 'true' => true, 'false' => false, default => $v };
+			}
+			$before = $t->getName();
+			$t = $this->targets->update($t, $input->getOption('name') ?? $t->getName(), $input->getOption('backend') ?? $t->getBackend(),
+				$input->getOption('auth') ?? $t->getAuth(), $options, $input->getOption('path') ?? $t->getBasePath());
+		} catch (\Throwable $e) {
+			$output->writeln('<error>' . $e->getMessage() . '</error>');
+			return 1;
+		}
+		$this->alerts->securityEvent('target_changed', ['target' => $before]);
+		$output->writeln(sprintf('Location <info>%s</info> updated; repository %s found with the new settings.', $t->getName(), (string)$t->getRepositoryId()));
+		return 0;
+	}
+}

lib/Command/Trash.php

@@ -7,7 +7,9 @@ declare(strict_types=1);
 
 namespace OCA\NgBackup\Command;
 
+use OCA\NgBackup\Format;
 use OCA\NgBackup\Service\KeyService;
+use OCA\NgBackup\Service\Schedule;
 use OCA\NgBackup\Service\TargetService;
 use Symfony\Component\Console\Command\Command;
 use Symfony\Component\Console\Helper\Table;
@@ -19,6 +21,7 @@ final class Trash extends Command {
 	public function __construct(
 		private TargetService $targets,
 		private KeyService $keys,
+		private Schedule $schedule,
 	) {
 		parent::__construct();
 	}
@@ -32,11 +35,14 @@ final class Trash extends Command {
 	protected function execute(InputInterface $input, OutputInterface $output): int {
 		$name = $input->getArgument('target');
 		$delay = $this->keys->deleteDelayDays() * 86400;
+		$zone = $this->schedule->get()['timezone'];
 		$rows = [];
 		foreach ($name === null ? $this->targets->list() : [$this->targets->get($name)] as $t) {
 			foreach ($this->targets->repository($t)->trash() as $id => $info) {
-				$rows[] = [$t->getName(), $id, (string)($info['time'] ?? ''), $info['label'], date('Y-m-d H:i', $info['forgottenAt']), $info['by'],
-					date('Y-m-d H:i', $info['forgottenAt'] + $delay)];
+				$time = $info['time'] ?? null;
+				$made = is_string($time) ? strtotime($time) : false;
+				$rows[] = [$t->getName(), $id, $made !== false ? Format::time($made, $zone) : '', $info['label'], Format::time($info['forgottenAt'], $zone), $info['by'],
+					Format::time($info['forgottenAt'] + $delay, $zone)];
 			}
 		}
 		if ($rows === []) {
@@ -44,6 +50,7 @@ final class Trash extends Command {
 			return 0;
 		}
 		(new Table($output))->setHeaders(['location', 'snapshot', 'made', 'label', 'removed', 'by', 'deleted after'])->setRows($rows)->render();
+		$output->writeln("Times in $zone. The retention policy keeps the newest snapshots and the last of each recent day, week and month; it moves the others here, and they are deleted permanently after " . $this->keys->deleteDelayDays() . ' days.');
 		return 0;
 	}
 }

lib/Command/Verify.php

@@ -0,0 +1,87 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\Command;
+
+use OCA\NgBackup\Service\TargetService;
+use OCA\NgBackup\Service\VerifyService;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputArgument;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Input\InputOption;
+use Symfony\Component\Console\Output\OutputInterface;
+
+final class Verify extends Command {
+	public function __construct(
+		private TargetService $targets,
+		private VerifyService $verify,
+	) {
+		parent::__construct();
+	}
+
+	protected function configure(): void {
+		$this->setName('backup:verify')
+			->setDescription('Checksum audit of a snapshot: every blob it needs must be in the (freshly re-checked) index and its pack present')
+			->addArgument('target', InputArgument::REQUIRED, 'Location name or id')
+			->addArgument('snapshot', InputArgument::REQUIRED, 'Snapshot id (see backup:list)')
+			->addOption('deep', null, InputOption::VALUE_NONE, 'Also download and decrypt every blob (verifies its authentication tag and content hash, not just that it is listed); much slower')
+			->setHelp(<<<'HELP'
+Without --deep this re-downloads and re-authenticates the index (never trusting the local cache)
+and confirms every blob the snapshot needs is listed and its pack is present -- fast, no blob
+content is read, so it cannot by itself catch a truncated or bit-rotted pack. With --deep every
+blob is also downloaded and decrypted, which fails loudly on exactly that even if the index still
+lists it -- the same verification an actual restore would do, run here deliberately instead of
+waiting to find out during one.
+
+While it runs it prints how far it is every 30 seconds; occ backup:status shows the same, and
+how the last check of each location ended.
+
+Run this periodically (cron, picking a sample of recent snapshots) rather than only right before
+you'd need to rely on a restore.
+
+Examples:
+  occ backup:verify offsite 537bf7e9c1a4...
+  occ backup:verify offsite 537bf7e9c1a4... --deep
+HELP);
+	}
+
+	protected function execute(InputInterface $input, OutputInterface $output): int {
+		try {
+			$target = $this->targets->get($input->getArgument('target'));
+			$ref = (string)$input->getArgument('snapshot');
+			$deep = (bool)$input->getOption('deep');
+			$onProgress = static function (array $state) use ($output): void {
+				$output->writeln(date('H:i:s') . ' ' . VerifyService::describe($state));
+			};
+			$result = str_starts_with($ref, 'users/')
+				? $this->verify->verifyUserExport($target, $ref, $deep, $onProgress)
+				: $this->verify->verify($target, $ref, $deep, $onProgress);
+		} catch (\Throwable $e) {
+			$output->writeln('<error>' . $e->getMessage() . '</error>');
+			return 1;
+		}
+		$output->writeln(sprintf('%d files, %d blobs checked%s.', $result['filesChecked'], $result['blobsChecked'],
+			$deep ? sprintf(' (%.1f MiB decrypted)', $result['bytesChecked'] / 1048576) : ''));
+		if ($result['missing'] !== []) {
+			$output->writeln('<error>' . count($result['missing']) . ' blob(s) missing from the index:</error> ' . implode(', ', $result['missing']));
+		}
+		if ($result['failed'] !== []) {
+			$output->writeln('<error>' . count($result['failed']) . ' blob(s) failed verification (corrupted or tampered):</error> ' . implode(', ', $result['failed']));
+		}
+		if ($result['unreadable'] !== []) {
+			$output->writeln('<error>' . count($result['unreadable']) . ' blob(s) could not be read from the location</error> (often a temporary storage '
+				. 'or network error: run the check again; if the same blobs stay unreadable, their pack may be damaged or truncated): '
+				. implode(', ', $result['unreadable']));
+			$output->writeln('Last read error: ' . $result['readError']);
+		}
+		if ($result['missing'] === [] && $result['failed'] === [] && $result['unreadable'] === []) {
+			$output->writeln('<info>OK</info>');
+			return 0;
+		}
+		return 1;
+	}
+}

lib/Controller/AdminApiController.php

@@ -47,18 +47,22 @@ final class AdminApiController extends Controller {
 		private \OCA\NgBackup\Service\AlertService $alerts,
 		private \OCA\NgBackup\Service\KeySlotService $slots,
 		private \OCA\NgBackup\Service\PruneService $prune,
+		private \OCA\NgBackup\Service\Schedule $schedule,
+		private \OCA\NgBackup\Service\CronHealth $cron,
 	) {
 		parent::__construct(Application::APP_ID, $request);
 	}
 
-	public function status(): JSONResponse {
+	/** @param bool $allRuns all runs instead of those of the last days (Status::RECENT_DAYS) */
+	public function status(bool $allRuns = false): JSONResponse {
 		$targets = [];
 		foreach ($this->targets->list() as $t) {
 			$targets[] = ['id' => $t->getId(), 'name' => $t->getName(), 'backend' => $t->getBackend(), 'path' => $t->getBasePath(),
 				'repositoryId' => $t->getRepositoryId(), 'createdAt' => $t->getCreatedAt(), 'appendOnly' => (bool)$t->getAppendOnly(),
 				'maxBytes' => $t->getMaxBytes(), 'storedBytes' => $this->alerts->lastStoredBytes($t)];
 		}
-		$runs = array_map(fn (Run $r) => $this->runJson($r), $this->runs->findRecent(15));
+		$shown = $this->runs->findShown($allRuns ? null : time() - \OCA\NgBackup\Command\Status::RECENT_DAYS * 86400);
+		$runs = array_map(fn (Run $r) => $this->runJson($r), $shown);
 		return new JSONResponse([
 			'key' => ['initialized' => $this->keys->isInitialized(), 'fingerprint' => $this->keys->fingerprint(),
 				'confirmation' => $this->keys->recoveryKitConfirmation(), 'everConfirmed' => $this->keys->isInitialized() && $this->keys->everConfirmed(),
@@ -68,10 +72,40 @@ final class AdminApiController extends Controller {
 			'confirmationPhrase' => KeyConfirm::CONFIRMATION,
 			'targets' => $targets,
 			'runs' => $runs,
-			'schedule' => $this->appConfig->getValueString(Application::APP_ID, 'schedule_time', ''),
+			'olderRuns' => $allRuns ? 0 : $this->runs->countAll() - count($shown),
+			'recentDays' => \OCA\NgBackup\Command\Status::RECENT_DAYS,
+			'schedule' => $this->schedule->get()['time'],
+			'scheduleTimezone' => $this->schedule->get()['timezone'],
+			'cron' => $this->cron->check(),
 		]);
 	}
 
+	/** Seconds of backup work one tick() does: well within a normal web request. */
+	public const TICK_SECONDS = 10.0;
+
+	/**
+	 * Move running backups forward from the open admin page, when background jobs do not run on a
+	 * working system cron (#13). The page calls this while a backup runs, so "Back up now" works
+	 * without cron as long as the page stays open; scheduled backups still need cron. With a
+	 * working system cron this does nothing: the background job does the work.
+	 */
+	public function tick(): JSONResponse {
+		if ($this->cron->check()['ok']) {
+			return new JSONResponse(['stepped' => 0]);
+		}
+		$deadline = microtime(true) + self::TICK_SECONDS;
+		$stepped = 0;
+		foreach ($this->runs->findRunning(null, BackupService::KIND_FULL) as $run) {
+			if (microtime(true) >= $deadline) {
+				break;
+			}
+			// step() returns at once when the background job (or another tab) holds the run.
+			$this->backups->step($run, $deadline);
+			$stepped++;
+		}
+		return new JSONResponse(['stepped' => $stepped]);
+	}
+
 	#[PasswordConfirmationRequired]
 	public function initKey(string $passphrase, int $deleteDelayDays = \OCA\NgBackup\Service\KeyService::DEFAULT_DELETE_DELAY, string $label = 'Slot 1'): JSONResponse {
 		try {
@@ -168,6 +202,7 @@ final class AdminApiController extends Controller {
 		return new JSONResponse($this->targets->availableBackends());
 	}
 
+	#[PasswordConfirmationRequired]
 	public function addTarget(string $name, string $backend, string $auth, array $options = [], string $path = 'ng_backup', ?float $maxGb = null): JSONResponse {
 		try {
 			$r = $this->targets->add($name, $backend, $auth, $options, $path);
@@ -180,6 +215,28 @@ final class AdminApiController extends Controller {
 		return new JSONResponse(['id' => $r['target']->getId(), 'created' => $r['created']]);
 	}
 
+	/** The stored settings for the edit form; password values are left out (null). */
+	#[PasswordConfirmationRequired]
+	public function targetSettings(int $id): JSONResponse {
+		$t = $this->targets->get((string)$id);
+		return new JSONResponse(['name' => $t->getName(), 'backend' => $t->getBackend(), 'auth' => $t->getAuth(),
+			'options' => $this->targets->editableOptions($t), 'path' => $t->getBasePath()]);
+	}
+
+	/** Options with a null value keep their stored value. */
+	#[PasswordConfirmationRequired]
+	public function updateTarget(int $id, string $name, string $backend, string $auth, array $options = [], string $path = 'ng_backup'): JSONResponse {
+		try {
+			$t = $this->targets->get((string)$id);
+			$before = $t->getName();
+			$t = $this->targets->update($t, $name, $backend, $auth, $options, $path);
+		} catch (\Throwable $e) {
+			return new JSONResponse(['error' => $e->getMessage()], Http::STATUS_BAD_REQUEST);
+		}
+		$this->alerts->securityEvent('target_changed', ['target' => $before]);
+		return new JSONResponse(['id' => $t->getId()]);
+	}
+
 	/** Size limit in GiB; null or 0 = unlimited. */
 	#[PasswordConfirmationRequired]
 	public function setTargetLimit(int $id, ?float $maxGb = null): JSONResponse {
@@ -213,12 +270,14 @@ final class AdminApiController extends Controller {
 		return new JSONResponse($this->runJson($run));
 	}
 
-	public function setSchedule(string $time): JSONResponse {
-		if ($time !== '' && !preg_match('/^([01]\d|2[0-3]):[0-5]\d$/', $time)) {
-			return new JSONResponse(['error' => 'Use HH:MM or empty'], Http::STATUS_BAD_REQUEST);
+	/** @param string $timezone the administrator's zone (the browser's); empty: keep the current one */
+	public function setSchedule(string $time, string $timezone = ''): JSONResponse {
+		try {
+			$this->schedule->set($time, $timezone !== '' ? $timezone : $this->schedule->get()['timezone']);
+		} catch (\InvalidArgumentException $e) {
+			return new JSONResponse(['error' => $e->getMessage()], Http::STATUS_BAD_REQUEST);
 		}
-		$this->appConfig->setValueString(Application::APP_ID, 'schedule_time', $time);
-		return new JSONResponse(['schedule' => $time]);
+		return new JSONResponse(['schedule' => $time, 'scheduleTimezone' => $this->schedule->get()['timezone']]);
 	}
 
 	public function snapshots(int $targetId): JSONResponse {
@@ -282,6 +341,7 @@ final class AdminApiController extends Controller {
 		return ['id' => $r->getId(), 'targetId' => $r->getTargetId(), 'kind' => $r->getKind(), 'status' => $r->getStatus(),
 			'phase' => $r->getPhase(), 'snapshotId' => $r->getSnapshotId(), 'snapshot' => $snapshot, 'startedAt' => $r->getStartedAt(),
 			'updatedAt' => $r->getUpdatedAt(), 'finishedAt' => $r->getFinishedAt(), 'error' => $r->getError(),
-			'stats' => json_decode($r->getStats() ?? 'null', true)];
+			'stats' => json_decode($r->getStats() ?? 'null', true), 'progress' => \OCA\NgBackup\Job\BackupRun::progressOf($r),
+			'waitingFor' => $r->getKind() === BackupService::KIND_FULL ? \OCA\NgBackup\Service\CronHealth::waitingFor($r) : null];
 	}
 }

lib/Crypto/KeyRing.php

@@ -96,6 +96,12 @@ final class KeyRing {
 	/** @param array{v:int, salt:string, ops:int, mem:int, nonce:string, key:string} $wrapped */
 	public static function unwrap(array $wrapped, #[\SensitiveParameter] string $passphrase): self {
 		$b64 = static fn (string $s): string => sodium_base642bin($s, SODIUM_BASE64_VARIANT_ORIGINAL);
+		// ops/mem come from unauthenticated JSON (kit file, repository config): bound them, so a
+		// damaged or crafted file cannot make the KDF use unbounded memory or time.
+		if ($wrapped['ops'] < SODIUM_CRYPTO_PWHASH_OPSLIMIT_INTERACTIVE || $wrapped['ops'] > SODIUM_CRYPTO_PWHASH_OPSLIMIT_SENSITIVE
+			|| $wrapped['mem'] < SODIUM_CRYPTO_PWHASH_MEMLIMIT_INTERACTIVE || $wrapped['mem'] > SODIUM_CRYPTO_PWHASH_MEMLIMIT_SENSITIVE) {
+			throw new CryptoException('Unsupported key derivation parameters (damaged or foreign key file)');
+		}
 		$kek = sodium_crypto_pwhash(SODIUM_CRYPTO_SECRETBOX_KEYBYTES, $passphrase, $b64($wrapped['salt']),
 			$wrapped['ops'], $wrapped['mem'], SODIUM_CRYPTO_PWHASH_ALG_ARGON2ID13);
 		$master = sodium_crypto_secretbox_open($b64($wrapped['key']), $b64($wrapped['nonce']), $kek);

lib/Crypto/StreamCipher.php

@@ -122,6 +122,7 @@ final class StreamCipher {
 	/** fread() may return short reads on network streams; keep reading until $length or EOF. */
 	private static function readFull($in, int $length): string {
 		$buffer = '';
+		$empty = 0;
 		while (strlen($buffer) < $length && !feof($in)) {
 			$chunk = fread($in, $length - strlen($buffer));
 			if ($chunk === false) {
@@ -132,8 +133,15 @@ final class StreamCipher {
 				if (feof($in)) {
 					break;
 				}
+				// A stalled network stream returns '' without EOF forever: back off, then give up
+				// (about a minute) instead of spinning at full CPU until the lease expires.
+				if (++$empty > 600) {
+					throw new CryptoException('Read stalled');
+				}
+				usleep(100000);
 				continue;
 			}
+			$empty = 0;
 			$buffer .= $chunk;
 		}
 		return $buffer;

lib/Db/DbDumper.php

@@ -23,8 +23,12 @@ use OCA\NgBackup\Repository\Repository;
  *   sets, so a single big SELECT would not stream).
  * - Each table becomes its own blob stream of JSON lines: a header line, then one JSON array per
  *   row. A table that did not change produces the same blobs and costs nothing in the next run.
- * - The schema itself is not dumped: it comes from Nextcloud's migrations on the instance that is
- *   restored into (same Nextcloud and app versions). The dump records those versions.
+ * - The structure of each table (columns, types, primary key, indexes) is recorded in the manifest,
+ *   so a restore can create a table that does not exist on the new instance, for example one left
+ *   behind by an app that was removed long ago. Tables that exist keep the structure the new
+ *   instance's migrations gave them.
+ * - Foreign keys are not checked while rows are loaded (tables are restored in name order, not in
+ *   dependency order), and are checked again before the restore commits.
  *
  * Phase 0 uses the Doctrine connection behind IDBConnection (private API) for schema
  * introspection; to be replaced by information_schema queries or a public API.
@@ -72,50 +76,57 @@ final class DbDumper {
 	public function dumpStep(Repository $repo, array $state, float $deadline, array &$stats): array {
 		$state['steps']++;
 		$sm = $this->db->createSchemaManager();
-		$this->db->setTransactionIsolation(TransactionIsolationLevel::REPEATABLE_READ);
-		$this->db->beginTransaction();
+		// A pack that fills up during the dump is uploaded right away; its index cache row must
+		// wait until the read-only transaction is over.
+		$repo->holdIndexCache();
 		try {
-			if ($this->db->getDatabasePlatform() instanceof \Doctrine\DBAL\Platforms\PostgreSQLPlatform) {
-				$this->db->executeStatement('SET TRANSACTION READ ONLY');
-			}
-			while ($state['i'] < count($state['tables'])) {
-				$table = $state['tables'][$state['i']];
-				$schema = $sm->introspectTable($table);
-				$writer = $repo->blobWriter($stats);
-				$hash = $state['hash'] !== null ? unserialize(base64_decode($state['hash']), ['allowed_classes' => [\HashContext::class]]) : hash_init('sha256');
-				if ($state['after'] === null && $state['segments'] === []) {
-					$writer->write($this->header($schema) . "\n");
+			$this->db->setTransactionIsolation(TransactionIsolationLevel::REPEATABLE_READ);
+			$this->db->beginTransaction();
+			try {
+				if ($this->db->getDatabasePlatform() instanceof \Doctrine\DBAL\Platforms\PostgreSQLPlatform) {
+					$this->db->executeStatement('SET TRANSACTION READ ONLY');
 				}
-				$complete = true;
-				foreach ($this->rowLines($schema, $state['after']) as [$key, $line]) {
-					$writer->write($line . "\n");
-					hash_update($hash, $line . "\n");
-					$state['rows']++;
-					$state['after'] = $key;
-					if (microtime(true) >= $deadline) {
-						$complete = false;
+				while ($state['i'] < count($state['tables'])) {
+					$table = $state['tables'][$state['i']];
+					$schema = $sm->introspectTable($table);
+					$writer = $repo->blobWriter($stats);
+					$hash = $state['hash'] !== null ? unserialize(base64_decode($state['hash']), ['allowed_classes' => [\HashContext::class]]) : hash_init('sha256');
+					if ($state['after'] === null && $state['segments'] === []) {
+						$writer->write($this->header($schema) . "\n");
+					}
+					$complete = true;
+					foreach ($this->rowLines($schema, $state['after']) as [$key, $line]) {
+						$writer->write($line . "\n");
+						hash_update($hash, $line . "\n");
+						$state['rows']++;
+						$state['after'] = $key;
+						if (microtime(true) >= $deadline) {
+							$complete = false;
+							break;
+						}
+					}
+					$state['segments'][] = $writer->finish();
+					$state['bytes'] += $writer->bytes();
+					if (!$complete) {
+						$state['hash'] = base64_encode(serialize($hash));
+						break;
+					}
+					$state['result'][$table] = ['blobs' => array_merge(...$state['segments']), 'rows' => $state['rows'],
+						'bytes' => $state['bytes'], 'sha256' => hash_final($hash), 'schema' => self::structure($schema)];
+					$state = array_merge($state, ['i' => $state['i'] + 1, 'after' => null, 'segments' => [], 'rows' => 0, 'bytes' => 0, 'hash' => null]);
+					if (microtime(true) >= $deadline && $state['i'] < count($state['tables'])) {
 						break;
 					}
 				}
-				$state['segments'][] = $writer->finish();
-				$state['bytes'] += $writer->bytes();
-				if (!$complete) {
-					$state['hash'] = base64_encode(serialize($hash));
-					break;
+				if ($state['i'] >= count($state['tables'])) {
+					$state['sequences'] = $this->sequenceStates($state['tables']);
+					$state['done'] = true;
 				}
-				$state['result'][$table] = ['blobs' => array_merge(...$state['segments']), 'rows' => $state['rows'],
-					'bytes' => $state['bytes'], 'sha256' => hash_final($hash)];
-				$state = array_merge($state, ['i' => $state['i'] + 1, 'after' => null, 'segments' => [], 'rows' => 0, 'bytes' => 0, 'hash' => null]);
-				if (microtime(true) >= $deadline && $state['i'] < count($state['tables'])) {
-					break;
-				}
-			}
-			if ($state['i'] >= count($state['tables'])) {
-				$state['sequences'] = $this->sequenceStates($state['tables']);
-				$state['done'] = true;
+			} finally {
+				$this->db->rollBack();
 			}
 		} finally {
-			$this->db->rollBack();
+			$repo->releaseIndexCache();
 		}
 		$repo->flushPacks();
 		return $state;
@@ -130,18 +141,38 @@ final class DbDumper {
 	 * Replace the contents of every table in the dump. Tables that exist but are not in the dump
 	 * are left alone (e.g. a newer app); the caller decides whether that is acceptable.
 	 *
-	 * @param array{tables: array<string, array{blobs: list<string>, rows: int}>} $manifest
+	 * @param array{tables: array<string, array{blobs: list<string>, rows: int, sha256: string, schema?: array}>, sequences?: array} $manifest
 	 */
-	public function restore(Repository $repo, array $manifest, ?array &$report = null): int {
-		$sm = $this->db->createSchemaManager();
-		$existing = array_flip($sm->listTableNames());
+	public function restore(Repository $repo, array $manifest, ?array &$report = null, ?callable $heartbeat = null, bool $skipMissing = false): int {
+		$report = ['skipped' => [], 'restored' => [], 'created' => [], 'missing' => []];
+		$source = self::dumpPrefix($manifest);
+		if ($source !== null && $source !== $this->prefix) {
+			// Every table would look missing and be created under the old prefix, unused.
+			throw new \RuntimeException("The backup's tables use the prefix '$source', this installation '{$this->prefix}'. Install Nextcloud again with 'dbtableprefix' => '$source' in config/config.php before occ maintenance:install, and restore again.");
+		}
+		$missing = $this->missingTables($manifest);
+		$unknown = array_values(array_filter($missing, fn (string $t) => !isset($manifest['tables'][$t]['schema'])));
+		if ($unknown !== [] && !$skipMissing) {
+			throw new \RuntimeException(self::describeMissing($unknown, $this->prefix));
+		}
+		// Tables the backup knows the structure of are created first (DDL is not transactional
+		// everywhere); tables it does not know are left out, as asked.
+		foreach ($missing as $table) {
+			if (isset($manifest['tables'][$table]['schema'])) {
+				$this->db->createSchemaManager()->createTable(self::tableFromStructure($table, $manifest['tables'][$table]['schema'], $this->tableOptions()));
+				$report['created'][] = $table;
+			} else {
+				$report['missing'][] = $table;
+			}
+		}
 		$total = 0;
-		$report = ['skipped' => [], 'restored' => []];
+		$foreignKeys = [];
 		$this->db->beginTransaction();
 		try {
+			$foreignKeys = $this->suspendForeignKeys(); // first: on SQLite it also takes the write lock
 			foreach ($manifest['tables'] as $table => $info) {
-				if (!isset($existing[$table])) {
-					throw new \RuntimeException("Table $table from the backup does not exist here (different app versions?)");
+				if (in_array($table, $report['missing'], true)) {
+					continue;
 				}
 				// Unchanged since the backup: leave it alone (much faster than delete + insert).
 				$live = $this->checksum($table);
@@ -175,6 +206,9 @@ final class DbDumper {
 					if (count($batch) >= self::INSERT_ROWS) {
 						$total += $this->insertBatch($table, $columns, $batch, $binary);
 						$batch = [];
+						if ($heartbeat !== null) {
+							$heartbeat();
+						}
 					}
 				}
 				if ($batch !== []) {
@@ -182,15 +216,235 @@ final class DbDumper {
 				}
 				$report['restored'][] = $table;
 			}
-			$this->restoreSequences($manifest['sequences'] ?? []);
+			// unchanged tables too: a restore that stopped earlier may have left their counters at 1
+			$this->restoreSequences($manifest['sequences'] ?? [], $report['missing'], array_merge($report['restored'], $report['skipped']));
+			$this->resumeForeignKeys($foreignKeys);
 			$this->db->commit();
+			// Foreign keys of the tables created above, now their rows are in. Not inside the
+			// transaction: MySQL commits on DDL. A failure is reported, not fatal: the data is
+			// restored either way.
+			foreach ($report['created'] as $table) {
+				$structure = $manifest['tables'][$table]['schema'] ?? [];
+				foreach ($structure['foreignKeys'] ?? [] as $fk) {
+					try {
+						$this->db->createSchemaManager()->createForeignKey(
+							new \Doctrine\DBAL\Schema\ForeignKeyConstraint($fk['columns'], $fk['table'], $fk['foreign'], $fk['name'], $fk['options'] ?? []),
+							$table);
+					} catch (\Throwable $e) {
+						$report['foreignKeyErrors'][] = $table . '.' . $fk['name'] . ': ' . $e->getMessage();
+					}
+				}
+			}
 		} catch (\Throwable $e) {
 			$this->db->rollBack();
+			// PostgreSQL rolls the dropped foreign keys back with the transaction; MySQL's session
+			// switch must be turned on again by hand.
+			if (in_array('SET FOREIGN_KEY_CHECKS = 1', $foreignKeys, true)) {
+				$this->db->executeStatement('SET FOREIGN_KEY_CHECKS = 1');
+			}
 			throw $e;
 		}
 		return $total;
 	}
 
+	/**
+	 * The table prefix of the instance the dump was made on (from its appconfig table), or null
+	 * when the dump has none.
+	 *
+	 */
+	public static function dumpPrefix(array $manifest): ?string {
+		/** @var list<string> $tables table names */
+		$tables = array_keys($manifest['tables'] ?? []);
+		foreach ($tables as $name) {
+			if (str_ends_with($name, 'appconfig') && !str_ends_with($name, '_ex_appconfig')) {
+				return substr($name, 0, -strlen('appconfig'));
+			}
+		}
+		return null;
+	}
+
+	/**
+	 * Tables in the dump that do not exist on this instance.
+	 *
+	 * @return list<string>
+	 */
+	public function missingTables(array $manifest): array {
+		$existing = array_flip($this->db->createSchemaManager()->listTableNames());
+		return array_values(array_filter(array_keys($manifest['tables']), fn (string $t) => !isset($existing[$t])));
+	}
+
+	/** One message for all missing tables of an older backup, grouped by the app they probably belong to. */
+	public static function describeMissing(array $tables, string $prefix): string {
+		$groups = [];
+		foreach ($tables as $t) {
+			$name = substr($t, strlen($prefix));
+			$groups[explode('_', $name, 2)[0]][] = $t;
+		}
+		$lines = [];
+		foreach ($groups as $app => $list) {
+			$lines[] = '- ' . $app . ': ' . implode(', ', $list);
+		}
+		return "These tables from the backup do not exist here, and this backup does not record their structure (made before 1.0.0-rc.2):\n"
+			. implode("\n", $lines)
+			. "\nInstall the apps they belong to (often apps that were removed or switched off long ago) and run the restore again, or leave these tables out with --skip-missing-tables.";
+	}
+
+	/**
+	 * Portable description of a table: enough to create it again, also on another database type.
+	 *
+	 * @return array{columns: list<array<string, mixed>>, pk: list<string>, indexes: list<array{name: string, columns: list<string>, unique: bool}>}
+	 */
+	private static function structure(\Doctrine\DBAL\Schema\Table $table): array {
+		$columns = [];
+		foreach ($table->getColumns() as $c) {
+			$columns[] = ['name' => $c->getName(), 'type' => \Doctrine\DBAL\Types\Type::lookupName($c->getType()),
+				'length' => $c->getLength(), 'precision' => $c->getPrecision(), 'scale' => $c->getScale(),
+				'unsigned' => $c->getUnsigned(), 'fixed' => $c->getFixed(), 'notnull' => $c->getNotnull(),
+				'default' => $c->getDefault(), 'autoincrement' => $c->getAutoincrement()];
+		}
+		$indexes = [];
+		foreach ($table->getIndexes() as $i) {
+			if (!$i->isPrimary()) {
+				// options holds the prefix lengths MySQL needs for indexes on long text columns
+				$indexes[] = ['name' => $i->getName(), 'columns' => array_values($i->getColumns()), 'unique' => $i->isUnique(),
+					'flags' => array_values($i->getFlags()), 'options' => $i->getOptions()];
+			}
+		}
+		$foreignKeys = [];
+		foreach ($table->getForeignKeys() as $fk) {
+			$foreignKeys[] = ['name' => $fk->getName(), 'columns' => array_values($fk->getLocalColumns()),
+				'table' => $fk->getForeignTableName(), 'foreign' => array_values($fk->getForeignColumns()), 'options' => $fk->getOptions()];
+		}
+		return ['columns' => $columns, 'pk' => array_values($table->getPrimaryKey()?->getColumns() ?? []), 'indexes' => $indexes,
+			'foreignKeys' => $foreignKeys];
+	}
+
+	/**
+	 * Table options for a table the restore creates: those of this installation's own tables.
+	 * On MySQL/MariaDB that is the character set and collation, as Nextcloud's tables have them
+	 * (utf8mb4, so emoji and other 4-byte characters fit); DBAL alone would use 3-byte utf8.
+	 *
+	 * @return array<string, mixed>
+	 * @psalm-suppress UndefinedClass the DBAL classes come with Nextcloud, not with this app
+	 */
+	private function tableOptions(): array {
+		$options = $this->db->createSchemaManager()->createSchemaConfig()->getDefaultTableOptions();
+		if ($this->db->getDatabasePlatform() instanceof \Doctrine\DBAL\Platforms\AbstractMySQLPlatform) {
+			$collation = $this->db->fetchOne('SELECT TABLE_COLLATION FROM information_schema.TABLES WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = ?',
+				[$this->prefix . 'appconfig']);
+			if (is_string($collation) && $collation !== '') {
+				$options['collation'] = $collation;
+				$options['charset'] = explode('_', $collation, 2)[0];
+				unset($options['collate']);
+			}
+		}
+		return $options;
+	}
+
+	/** @param array<string, mixed> $options table options (see tableOptions()) */
+	private static function tableFromStructure(string $name, array $structure, array $options = []): \Doctrine\DBAL\Schema\Table {
+		$table = new \Doctrine\DBAL\Schema\Table($name, [], [], [], [], $options);
+		foreach ($structure['columns'] as $c) {
+			$table->addColumn($c['name'], $c['type'], array_filter([
+				'length' => $c['length'], 'precision' => $c['precision'], 'scale' => $c['scale'],
+				'unsigned' => $c['unsigned'], 'fixed' => $c['fixed'], 'notnull' => $c['notnull'],
+				'default' => $c['default'], 'autoincrement' => $c['autoincrement'],
+			], fn ($v) => $v !== null));
+		}
+		if ($structure['pk'] !== []) {
+			$table->setPrimaryKey($structure['pk']);
+		}
+		foreach ($structure['indexes'] as $i) {
+			$i['unique']
+				? $table->addUniqueIndex($i['columns'], $i['name'], $i['options'] ?? [])
+				: $table->addIndex($i['columns'], $i['name'], $i['flags'] ?? [], $i['options'] ?? []);
+		}
+		return $table;
+	}
+
+	/**
+	 * Stop checking foreign keys while rows are loaded in name order. PostgreSQL has no session
+	 * switch for this without superuser rights, so its foreign keys of Nextcloud tables are dropped
+	 * here and added back (and so checked) by resumeForeignKeys(), inside the same transaction.
+	 *
+	 * @return list<string> statements that restore the foreign keys
+	 */
+	private function suspendForeignKeys(): array {
+		$platform = $this->db->getDatabasePlatform();
+		if ($platform instanceof \Doctrine\DBAL\Platforms\PostgreSQLPlatform) {
+			$rows = $this->db->fetchAllAssociative(
+				"SELECT conrelid::regclass::text AS tbl, conname, pg_get_constraintdef(oid) AS def
+				 FROM pg_constraint WHERE contype = 'f' AND connamespace = current_schema()::regnamespace");
+			$restore = [];
+			foreach ($rows as $r) {
+				if (!str_starts_with(trim($r['tbl'], '"'), $this->prefix)) {
+					continue;
+				}
+				$this->db->executeStatement(sprintf('ALTER TABLE %s DROP CONSTRAINT %s', $r['tbl'], $this->db->quoteIdentifier($r['conname'])));
+				$restore[] = sprintf('ALTER TABLE %s ADD CONSTRAINT %s %s', $r['tbl'], $this->db->quoteIdentifier($r['conname']), $r['def']);
+			}
+			return $restore;
+		}
+		if ($platform instanceof \Doctrine\DBAL\Platforms\AbstractMySQLPlatform) {
+			// MySQL does not check rows again when FOREIGN_KEY_CHECKS goes back to 1, and its DDL
+			// would commit the transaction halfway. So every foreign key is checked explicitly,
+			// with a query that finds rows pointing at nothing (resumeForeignKeys()).
+			$rows = $this->db->fetchAllAssociative(
+				'SELECT TABLE_NAME AS tbl, CONSTRAINT_NAME AS name, COLUMN_NAME AS col, REFERENCED_TABLE_NAME AS rtbl, REFERENCED_COLUMN_NAME AS rcol
+				 FROM information_schema.KEY_COLUMN_USAGE
+				 WHERE TABLE_SCHEMA = DATABASE() AND REFERENCED_TABLE_NAME IS NOT NULL
+				 ORDER BY TABLE_NAME, CONSTRAINT_NAME, ORDINAL_POSITION');
+			$keys = [];
+			foreach ($rows as $r) {
+				if (str_starts_with((string)$r['tbl'], $this->prefix)) {
+					$keys[$r['tbl'] . "\0" . $r['name']][] = $r;
+				}
+			}
+			$q = fn (string $i): string => $this->db->quoteIdentifier($i);
+			$checks = ['SET FOREIGN_KEY_CHECKS = 1'];
+			foreach ($keys as $parts) {
+				$join = implode(' AND ', array_map(fn (array $r): string => 'c.' . $q($r['col']) . ' = p.' . $q($r['rcol']), $parts));
+				$set = implode(' AND ', array_map(fn (array $r): string => 'c.' . $q($r['col']) . ' IS NOT NULL', $parts));
+				$checks[] = sprintf('SELECT COUNT(*) FROM %s c LEFT JOIN %s p ON %s WHERE %s AND p.%s IS NULL /* %s */',
+					$q($parts[0]['tbl']), $q($parts[0]['rtbl']), $join, $set, $q($parts[0]['rcol']), $parts[0]['name']);
+			}
+			$this->db->executeStatement('SET FOREIGN_KEY_CHECKS = 0');
+			return $checks;
+		}
+		if ($platform instanceof \Doctrine\DBAL\Platforms\SqlitePlatform) {
+			// SQLite (WAL) starts a transaction as a reader. When another process (a cron job, the
+			// installer still finishing) writes between our first read and our first write, that
+			// write fails at once with "database is locked": no waiting helps a reader whose view
+			// is out of date. Take the write lock first, so we wait for the other writer instead
+			// and it waits for us after that.
+			$this->db->executeStatement('DELETE FROM ' . $this->db->quoteIdentifier($this->prefix . 'appconfig') . ' WHERE 0 = 1');
+			$this->db->executeStatement('PRAGMA defer_foreign_keys = ON'); // checked at commit
+		}
+		return [];
+	}
+
+	/**
+	 * Check the foreign keys again; a row that breaks one fails the restore here, before it commits.
+	 * Statements add them back (PostgreSQL) or switch the checks on (MySQL); queries count the rows
+	 * that point at nothing (MySQL) and must find none.
+	 */
+	private function resumeForeignKeys(array $statements): void {
+		foreach ($statements as $sql) {
+			try {
+				if (str_starts_with($sql, 'SELECT ')) {
+					$orphans = (int)$this->db->fetchOne($sql);
+					if ($orphans > 0) {
+						throw new \RuntimeException("$orphans rows point at nothing");
+					}
+				} else {
+					$this->db->executeStatement($sql);
+				}
+			} catch (\Throwable $e) {
+				throw new \RuntimeException('The restored data breaks a foreign key (' . $sql . '): ' . $e->getMessage(), 0, $e);
+			}
+		}
+	}
+
 	/** Same checksum as dump(): sha256 over the row lines in primary-key order. */
 	public function checksum(string $table): array {
 		$hash = hash_init('sha256');
@@ -253,7 +507,11 @@ final class DbDumper {
 					} elseif (is_string($row[$i]) && !mb_check_encoding($row[$i], 'UTF-8')) {
 						// Keep invalid UTF-8 byte-exact instead of substituting characters.
 						$row[$i] = ['$b' => base64_encode($row[$i])];
-					} elseif (is_int($row[$i]) || is_float($row[$i]) || is_bool($row[$i])) {
+					} elseif (is_float($row[$i])) {
+						// var_export uses serialize_precision (shortest exact form), not the lossy
+						// 14-digit 'precision' of a (string) cast.
+						$row[$i] = var_export($row[$i], true);
+					} elseif (is_int($row[$i]) || is_bool($row[$i])) {
 						// Normalise: drivers differ in returning numbers as int or string.
 						$row[$i] = (string)(is_bool($row[$i]) ? (int)$row[$i] : $row[$i]);
 					}
@@ -345,11 +603,21 @@ final class DbDumper {
 		return $name;
 	}
 
-	private function restoreSequences(array $sequences): void {
+	/**
+	 * @param list<string> $leftOut tables not restored (--skip-missing-tables): they do not exist here
+	 * @param list<string> $restored tables restored or unchanged: their other counters go after their data
+	 */
+	private function restoreSequences(array $sequences, array $leftOut = [], array $restored = []): void {
 		if (!$this->db->getDatabasePlatform() instanceof \Doctrine\DBAL\Platforms\PostgreSQLPlatform) {
 			return;
 		}
+		$leftOut = array_flip($leftOut);
+		$set = [];
 		foreach ($sequences as $info) {
+			if (isset($leftOut[$info['table']])) {
+				continue;
+			}
+			$set[$info['table'] . '.' . $info['column']] = true;
 			$seq = $this->db->fetchOne('SELECT pg_get_serial_sequence(quote_ident(?), ?)', [$info['table'], $info['column']]);
 			if ($seq === false || $seq === null) {
 				continue;
@@ -364,5 +632,26 @@ final class DbDumper {
 					[\Doctrine\DBAL\ParameterType::STRING, \Doctrine\DBAL\ParameterType::INTEGER, \Doctrine\DBAL\ParameterType::BOOLEAN]);
 			}
 		}
+		// A backup from MySQL/MariaDB or SQLite records no counters (those derive them from the
+		// data): every other counter of a restored table goes after its data, or new rows (a new
+		// file, an activity) would collide with restored ones.
+		$restored = array_flip($restored);
+		$rows = $this->db->fetchAllAssociative(
+			"SELECT c.table_name, c.column_name, pg_get_serial_sequence(quote_ident(c.table_name), c.column_name) AS seq
+			 FROM information_schema.columns c
+			 WHERE c.table_schema = current_schema() AND pg_get_serial_sequence(quote_ident(c.table_name), c.column_name) IS NOT NULL");
+		foreach ($rows as $r) {
+			if (!isset($restored[$r['table_name']]) || isset($set[$r['table_name'] . '.' . $r['column_name']])) {
+				continue;
+			}
+			$max = (int)$this->db->fetchOne(sprintf('SELECT COALESCE(MAX(%s), 0) FROM %s',
+				$this->db->quoteIdentifier($r['column_name']), $this->db->quoteIdentifier($r['table_name'])));
+			// never backwards: a counter already past the data stays where it is
+			$state = $this->db->fetchAssociative('SELECT last_value, is_called FROM ' . self::sequenceIdentifier($r['seq']));
+			$next = $state === false ? 1 : (int)$state['last_value'] + ($state['is_called'] ? 1 : 0);
+			if ($next <= $max) {
+				$this->db->executeQuery('SELECT setval(CAST(? AS regclass), ?, false)', [$r['seq'], $max + 1]);
+			}
+		}
 	}
 }

lib/Db/DbIndexCache.php

@@ -30,19 +30,91 @@ final class DbIndexCache implements IIndexCache {
 	}
 
 	public function put(string $repositoryId, string $packId, array $entries): void {
+		try {
+			$this->insert($repositoryId, $packId, $entries);
+		} catch (Exception $e) {
+			if ($e->getReason() !== Exception::REASON_UNIQUE_CONSTRAINT_VIOLATION) {
+				throw $e;
+			}
+		}
+	}
+
+	/**
+	 * In one transaction: on PostgreSQL with its default settings every statement of its own
+	 * waits for a disk sync, which made 27,547 rows take more than 6 minutes. Rows already there
+	 * are replaced. Should the transaction fail (another process writing the same rows), the
+	 * rows are written one by one, keeping rows that are already there.
+	 */
+	public function putMany(string $repositoryId, array $packs): void {
+		if ($packs === []) {
+			return;
+		}
+		try {
+			$this->transaction(function () use ($repositoryId, $packs): void {
+				$this->remove($repositoryId, array_keys($packs));
+				$this->insertAll($repositoryId, $packs);
+			});
+		} catch (\Throwable $e) {
+			if ($this->db->inTransaction()) {
+				throw $e; // a transaction of the caller's, which may be spoilt now
+			}
+			foreach ($packs as $packId => $entries) {
+				$this->put($repositoryId, $packId, $entries);
+			}
+		}
+	}
+
+	/** Drop the cached index of a repository that no location uses any more. */
+	public function forget(string $repositoryId): void {
+		$qb = $this->db->getQueryBuilder();
+		$qb->delete('ngb_index')->where($qb->expr()->eq('repository_id', $qb->createNamedParameter($repositoryId)));
+		$qb->executeStatement();
+	}
+
+	/** All or nothing: when it fails, the cache stays as it was. */
+	public function replaceAll(string $repositoryId, array $packs): void {
+		$this->transaction(function () use ($repositoryId, $packs): void {
+			$qb = $this->db->getQueryBuilder();
+			$qb->delete('ngb_index')->where($qb->expr()->eq('repository_id', $qb->createNamedParameter($repositoryId)));
+			$qb->executeStatement();
+			$this->insertAll($repositoryId, $packs);
+		});
+	}
+
+	/** Run $write in a transaction of its own, or as part of the caller's when there is one. */
+	private function transaction(\Closure $write): void {
+		if ($this->db->inTransaction()) {
+			$write();
+			return;
+		}
+		$this->db->beginTransaction();
+		try {
+			$write();
+			$this->db->commit();
+		} catch (\Throwable $e) {
+			if ($this->db->inTransaction()) {
+				$this->db->rollBack();
+			}
+			throw $e;
+		}
+	}
+
+	/** @param array<string, list<array{id:string, offset:int, length:int, raw:int, flags:int}>> $packs */
+	private function insertAll(string $repositoryId, array $packs): void {
+		foreach ($packs as $packId => $entries) {
+			$this->insert($repositoryId, $packId, $entries);
+		}
+	}
+
+	/** @param list<array{id:string, offset:int, length:int, raw:int, flags:int}> $entries */
+	private function insert(string $repositoryId, string $packId, array $entries): void {
 		$qb = $this->db->getQueryBuilder();
 		$qb->insert('ngb_index')->values([
 			'repository_id' => $qb->createNamedParameter($repositoryId),
 			'pack_id' => $qb->createNamedParameter($packId),
 			'entries' => $qb->createNamedParameter(json_encode($entries, JSON_THROW_ON_ERROR)),
 		]);
-		try {
-			$qb->executeStatement();
-		} catch (Exception $e) {
-			if ($e->getReason() !== Exception::REASON_UNIQUE_CONSTRAINT_VIOLATION) {
-				throw $e;
-			}
-		}
+		$qb->executeStatement();
 	}
 
 	public function remove(string $repositoryId, array $packIds): void {

lib/Db/RunMapper.php

@@ -17,6 +17,36 @@ final class RunMapper extends QBMapper {
 		parent::__construct($db, 'ngb_runs', Run::class);
 	}
 
+	/**
+	 * Write $run only if it is still running and unchanged since it was loaded (updated_at
+	 * $loadedAt), in one statement: two processes that loaded the same run cannot both write it.
+	 * The new updated_at is always later than $loadedAt, so every write is seen as a change.
+	 *
+	 * @return Run|null the written run, or null when another process wrote it first
+	 */
+	public function updateIfUnchanged(Run $run, int $loadedAt): ?Run {
+		$run->setUpdatedAt(max(time(), $loadedAt + 1));
+		$types = $run->getFieldTypes();
+		$qb = $this->db->getQueryBuilder();
+		$qb->update($this->getTableName());
+		foreach (array_keys($run->getUpdatedFields()) as $field) {
+			if ($field === 'id') {
+				continue;
+			}
+			$value = $run->{'get' . ucfirst($field)}();
+			$type = ($types[$field] ?? 'string') === 'integer' ? IQueryBuilder::PARAM_INT : IQueryBuilder::PARAM_STR;
+			$qb->set($run->propertyToColumn($field), $qb->createNamedParameter($value, $value === null ? IQueryBuilder::PARAM_NULL : $type));
+		}
+		$qb->where($qb->expr()->eq('id', $qb->createNamedParameter($run->getId(), IQueryBuilder::PARAM_INT)))
+			->andWhere($qb->expr()->eq('status', $qb->createNamedParameter(Run::RUNNING)))
+			->andWhere($qb->expr()->eq('updated_at', $qb->createNamedParameter($loadedAt, IQueryBuilder::PARAM_INT)));
+		if ($qb->executeStatement() !== 1) {
+			return null;
+		}
+		$run->resetUpdatedFields();
+		return $run;
+	}
+
 	public function find(int $id): Run {
 		$qb = $this->db->getQueryBuilder();
 		$qb->select('*')->from($this->getTableName())->where($qb->expr()->eq('id', $qb->createNamedParameter($id, IQueryBuilder::PARAM_INT)));
@@ -43,6 +73,51 @@ final class RunMapper extends QBMapper {
 		return $this->findEntities($qb);
 	}
 
+	/**
+	 * The runs to list, newest first: those started at or after $since, those still running, and
+	 * at least the newest $atLeast, so the list is never empty after a quiet week. All runs when
+	 * $since is null.
+	 *
+	 * @return list<Run>
+	 */
+	public function findShown(?int $since, int $atLeast = 5): array {
+		$qb = $this->db->getQueryBuilder();
+		$qb->select('*')->from($this->getTableName())->orderBy('id', 'DESC');
+		if ($since === null) {
+			return $this->findEntities($qb);
+		}
+		$qb->where($qb->expr()->orX(
+			$qb->expr()->gte('started_at', $qb->createNamedParameter($since, IQueryBuilder::PARAM_INT)),
+			$qb->expr()->eq('status', $qb->createNamedParameter(Run::RUNNING)),
+		));
+		$runs = [];
+		foreach ([...$this->findEntities($qb), ...$this->findRecent($atLeast)] as $r) {
+			$runs[$r->getId()] = $r;
+		}
+		krsort($runs);
+		return array_values($runs);
+	}
+
+	public function countAll(): int {
+		$qb = $this->db->getQueryBuilder();
+		$qb->select($qb->func()->count('*', 'n'))->from($this->getTableName());
+		$result = $qb->executeQuery();
+		$n = (int)$result->fetchOne();
+		$result->closeCursor();
+		return $n;
+	}
+
+	/** @return list<Run> runs of $kind started at or after $since, newest first */
+	public function startedSince(int $targetId, string $kind, int $since): array {
+		$qb = $this->db->getQueryBuilder();
+		$qb->select('*')->from($this->getTableName())
+			->where($qb->expr()->eq('target_id', $qb->createNamedParameter($targetId, IQueryBuilder::PARAM_INT)))
+			->andWhere($qb->expr()->eq('kind', $qb->createNamedParameter($kind)))
+			->andWhere($qb->expr()->gte('started_at', $qb->createNamedParameter($since, IQueryBuilder::PARAM_INT)))
+			->orderBy('id', 'DESC');
+		return $this->findEntities($qb);
+	}
+
 	public function lastFinished(int $targetId, string $kind): ?Run {
 		$qb = $this->db->getQueryBuilder();
 		$qb->select('*')->from($this->getTableName())

lib/Format.php

@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup;
+
+final class Format {
+	/** "12:10:13", or "1d 12:10:13" from a day on (a long first backup takes days). */
+	public static function duration(int $seconds): string {
+		$seconds = max(0, $seconds);
+		$days = intdiv($seconds, 86400);
+		$time = gmdate('H:i:s', $seconds % 86400);
+		return $days > 0 ? $days . 'd ' . $time : $time;
+	}
+
+	/**
+	 * "2026-10-29 04:30" in $zone. Nextcloud runs PHP in UTC; occ shows times in the zone of the
+	 * schedule, the administrator's, as the web interface does.
+	 *
+	 * @param non-empty-string $zone
+	 */
+	public static function time(int $timestamp, string $zone): string {
+		return (new \DateTimeImmutable('@' . $timestamp))->setTimezone(new \DateTimeZone($zone))->format('Y-m-d H:i');
+	}
+}

lib/Job/BackupRun.php

@@ -49,9 +49,11 @@ final class BackupRun {
 	public static function step(Repository $repo, array $state, float $deadline): array {
 		$state['steps']++;
 		if ($state['phase'] === 'files') {
-			$walker = new TreeWalker($state['roots'], $state['exclude']);
-			$parent = new ParentCursor($repo, $state['parent'], $state['parentPos']);
 			$stats = $state['stats'];
+			$walker = new TreeWalker($state['roots'], $state['exclude'], function (string $logical) use (&$state, &$stats): void {
+				self::recordUnreadable($state, $stats, $logical);
+			});
+			$parent = new ParentCursor($repo, $state['parent'], $state['parentPos']);
 			$lines = [];
 			$finishedWalk = true;
 
@@ -68,15 +70,20 @@ final class BackupRun {
 					$stats['reused']++;
 				} else {
 					$cur = $state['cur'];
-					if ($cur === null || $cur['path'] !== $logical || $cur['version'] !== $version) {
-						if ($cur !== null && $cur['path'] === $logical) {
-							$stats['retried'] = ($stats['retried'] ?? 0) + 1; // changed since the previous step
+					if ($cur !== null && $cur['path'] === $logical && $cur['version'] !== $version) {
+						// Changed since the previous step: start over, unless it keeps changing.
+						if (self::countRetry($state, $stats, $logical)) {
+							$cur['version'] = $version;
+						} else {
+							$cur = null;
 						}
+					}
+					if ($cur === null || $cur['path'] !== $logical) {
 						$cur = ['path' => $logical, 'offset' => 0, 'blobs' => [], 'version' => $version];
 					}
-					$fh = fopen($path, 'rb');
+					$fh = @fopen($path, 'rb');
 					if ($fh === false) {
-						$stats['unreadable'] = ($stats['unreadable'] ?? 0) + 1;
+						self::recordUnreadable($state, $stats, $logical);
 						$state['cur'] = null;
 						continue;
 					}
@@ -91,12 +98,17 @@ final class BackupRun {
 						}
 					}
 					fclose($fh);
-					if (Repository::fileVersion($path) !== $cur['version']) {
-						// Changed while reading: read it again from the start (now or next step).
-						$stats['retried'] = ($stats['retried'] ?? 0) + 1;
-						$state['cur'] = null;
-						$finishedWalk = false;
-						break;
+					$now = Repository::fileVersion($path);
+					if ($now !== $cur['version']) {
+						if (!self::countRetry($state, $stats, $logical)) {
+							// Changed while reading: read it again from the start (now or next step).
+							$state['cur'] = null;
+							$finishedWalk = false;
+							break;
+						}
+						// Keeps changing (a live database, VM image or log): keep what was read,
+						// like any copy of a file in use, and report it instead of retrying forever.
+						$cur['version'] = $now;
 					}
 					if (!$complete) {
 						$state['cur'] = $cur;
@@ -104,6 +116,7 @@ final class BackupRun {
 						break;
 					}
 					$blobs = $cur['blobs'];
+					$size = $cur['offset'];
 					$state['cur'] = null;
 					$stats['read']++;
 				}
@@ -127,25 +140,112 @@ final class BackupRun {
 			$state['parentPos'] = $parent->position();
 			$state['stats'] = $stats;
 			if ($finishedWalk) {
+				// The snapshot is written in a step of its own, with its own time: after a long
+				// run it reads back thousands of segments, and the run reports that it got here.
 				$state['phase'] = 'finish';
 			}
+			return $state;
 		}
 
 		if ($state['phase'] === 'finish') {
-			$segments = $state['segments'];
-			$repo->writeSnapshot($state['snapshot'],
+			// Every segment ends with a newline, so they read as one stream: fetched together,
+			// several at a time where the location allows it.
+			$repo->putSnapshot($state['snapshot'],
 				['time' => $state['started'], 'parent' => $state['parent'], 'label' => $state['label'],
-					'roots' => array_keys($state['roots']), 'stats' => $state['stats']] + $state['meta'],
-				(function () use ($repo, $segments) {
-					foreach ($segments as $blobs) {
-						yield from $repo->readLines($blobs);
-					}
-				})());
-			$state['phase'] = 'done';
+					'roots' => array_keys($state['roots']), 'stats' => $state['stats'],
+					'warnings' => self::warnings($state)] + $state['meta'],
+				$repo->readLines(array_values(array_merge(...$state['segments']))));
+			$state['phase'] = 'commit';
 		}
 		return $state;
 	}
 
+	/**
+	 * Progress of the files phase as a fraction (at most 0.99 until it is done), or null without an
+	 * estimate. Bytes of a large file that is still being read count too.
+	 *
+	 * @return array{fraction: float, approximate: bool}|null
+	 */
+	public static function progress(array $state): ?array {
+		$estimate = $state['estimate'] ?? null;
+		if (($state['phase'] ?? null) !== 'files' || !is_array($estimate) || ($estimate['bytes'] ?? 0) <= 0) {
+			return null;
+		}
+		$done = (int)($state['stats']['bytes'] ?? 0) + (int)($state['cur']['offset'] ?? 0);
+		return ['fraction' => min(0.99, $done / (int)$estimate['bytes']), 'approximate' => (bool)($estimate['approximate'] ?? true)];
+	}
+
+	/**
+	 * progress() of a run in its files phase; in its database phase, the tables dumped so far.
+	 *
+	 * @return array{fraction: float, approximate: bool, tables?: int, totalTables?: int}|null
+	 */
+	public static function progressOf(\OCA\NgBackup\Db\Run $run): ?array {
+		if ($run->getStatus() !== \OCA\NgBackup\Db\Run::RUNNING || !in_array($run->getPhase(), ['db', 'files'], true)) {
+			return null;
+		}
+		try {
+			$state = json_decode($run->getState(), true, 512, JSON_THROW_ON_ERROR);
+		} catch (\JsonException) {
+			return null;
+		}
+		if ($run->getPhase() === 'db') {
+			// Tables dumped so far, as of the last step (none known before the first step ends)
+			$tables = count($state['dump']['tables'] ?? []);
+			return $tables > 0
+				? ['fraction' => min(1.0, ($state['dump']['i'] ?? 0) / $tables), 'approximate' => false,
+					'tables' => (int)($state['dump']['i'] ?? 0), 'totalTables' => $tables]
+				: null;
+		}
+		return is_array($state['files'] ?? null) ? self::progress($state['files']) : null;
+	}
+
+	/**
+	 * A file or directory that could not be read: it is missing from this snapshot. Remembered (first
+	 * 1000, deduplicated across steps) so the run can report it instead of silently succeeding.
+	 */
+	private static function recordUnreadable(array &$state, array &$stats, string $logical): void {
+		if (isset($state['unreadable'][$logical])) {
+			return;
+		}
+		if (count($state['unreadable'] ?? []) < 1000) {
+			$state['unreadable'][$logical] = true;
+		}
+		$stats['unreadable'] = ($stats['unreadable'] ?? 0) + 1;
+	}
+
+	/** @return array{unreadable: list<string>, changing: list<string>} examples for the report (first 50 each) */
+	public static function warnings(array $state): array {
+		return [
+			'unreadable' => array_slice(array_map('strval', array_keys($state['unreadable'] ?? [])), 0, 50),
+			'changing' => array_slice(array_map('strval', array_values($state['changing'] ?? [])), 0, 50),
+		];
+	}
+
+	/** Retries of one file that changes while it is read, before its last read is kept anyway. */
+	public const MAX_RETRIES = 3;
+
+	/**
+	 * Count a retry of $logical. Returns true once it has changed MAX_RETRIES times: the caller then
+	 * keeps the data it read, and the file is listed in $state['changing'] (first 50) for the report.
+	 */
+	private static function countRetry(array &$state, array &$stats, string $logical): bool {
+		$stats['retried'] = ($stats['retried'] ?? 0) + 1;
+		$n = (($state['retryPath'] ?? null) === $logical ? (int)($state['retryCount'] ?? 0) : 0) + 1;
+		$state['retryPath'] = $logical;
+		$state['retryCount'] = $n;
+		if ($n < self::MAX_RETRIES) {
+			return false;
+		}
+		if ($n === self::MAX_RETRIES) {
+			$stats['changing'] = ($stats['changing'] ?? 0) + 1;
+			if (count($state['changing'] ?? []) < 50) {
+				$state['changing'][] = $logical;
+			}
+		}
+		return true;
+	}
+
 	private static function readFull($fh, int $length): string {
 		$buffer = '';
 		while (strlen($buffer) < $length && !feof($fh)) {

lib/Job/TreeWalker.php

@@ -23,6 +23,8 @@ final class TreeWalker {
 	public function __construct(
 		private array $roots,
 		private array $exclude = [],
+		/** Called with the logical path of a directory that cannot be listed. */
+		private ?\Closure $onUnreadable = null,
 	) {
 	}
 
@@ -57,6 +59,9 @@ final class TreeWalker {
 		}
 		$names = @scandir($abs);
 		if ($names === false) {
+			if ($this->onUnreadable !== null) {
+				($this->onUnreadable)($logical === '' ? '/' : $logical);
+			}
 			return;
 		}
 		$names = array_values(array_diff($names, ['.', '..']));

lib/Migration/Version000006Date20261018000000.php

@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\Migration;
+
+use Closure;
+use OCP\IDBConnection;
+use OCP\Migration\IOutput;
+use OCP\Migration\SimpleMigrationStep;
+
+/**
+ * Removing a location left the cached index of its repository behind (tens of thousands of rows
+ * for a large backup). Drop the cache of repositories no location uses any more.
+ */
+final class Version000006Date20261018000000 extends SimpleMigrationStep {
+	public function __construct(
+		private IDBConnection $db,
+	) {
+	}
+
+	public function postSchemaChange(IOutput $output, Closure $schemaClosure, array $options): void {
+		$used = $this->db->getQueryBuilder();
+		$used->select('repository_id')->from('ngb_targets')->where($used->expr()->isNotNull('repository_id'));
+		$keep = array_column($used->executeQuery()->fetchAll(), 'repository_id');
+		$delete = $this->db->getQueryBuilder();
+		$delete->delete('ngb_index');
+		if ($keep !== []) {
+			$delete->where($delete->expr()->notIn('repository_id', $delete->createNamedParameter($keep, \OCP\DB\QueryBuilder\IQueryBuilder::PARAM_STR_ARRAY)));
+		}
+		$removed = $delete->executeStatement();
+		if ($removed > 0) {
+			$output->info("Removed $removed cached index rows of locations that no longer exist");
+		}
+	}
+}

lib/Notification/Notifier.php

@@ -42,12 +42,19 @@ final class Notifier implements INotifier {
 					: $l->t('Backup to %s failed', [$p['target']]));
 				$notification->setParsedMessage((string)($p['error'] ?? ''));
 				break;
+			case 'run_warnings':
+				$notification->setParsedSubject($l->t('Backup to %1$s finished with warnings: %2$s unreadable, %3$s changed while being read', [$p['target'], $p['unreadable'], $p['changing']]));
+				$notification->setParsedMessage($l->t('Unreadable files and folders are missing from this backup (check their permissions). Files that kept changing were saved as they were while being read. Examples: %s', [$p['examples'] ?? '']));
+				break;
 			case 'quota_warning':
 				$notification->setParsedSubject($l->t('Backup location %1$s is at %2$s%% of its limit (%3$s of %4$s)', [$p['target'], $p['percent'], $p['used'], $p['limit']]));
 				$notification->setParsedMessage($l->t('Backups stop when the limit is reached. Raise the limit, or let the retention policy remove older backups.'));
 				break;
 			case 'backup_stale':
-				$notification->setParsedSubject($l->t('No successful backup to %1$s since %2$s', [$p['target'], $p['since']]));
+				// 'never' was stored by 0.9.4 and earlier
+				$notification->setParsedSubject(in_array($p['since'] ?? '', ['', 'never'], true)
+					? $l->t('No successful backup to %s yet', [$p['target']])
+					: $l->t('No successful backup to %1$s since %2$s', [$p['target'], $p['since']]));
 				$notification->setParsedMessage($l->t('Check the backup settings and the server log.'));
 				break;
 			case 'security_event':
@@ -55,6 +62,7 @@ final class Notifier implements INotifier {
 				$notification->setParsedSubject(match ($p['event'] ?? '') {
 					'kit_downloaded' => $l->t('%s downloaded the backup recovery kit', [$who]),
 					'target_removed' => $l->t('%1$s removed backup location %2$s', [$who, $p['target'] ?? '']),
+					'target_changed' => $l->t('%1$s changed the connection settings of backup location %2$s', [$who, $p['target'] ?? '']),
 					'append_only_off' => $l->t('%1$s turned off append-only for backup location %2$s', [$who, $p['target'] ?? '']),
 					'retention_changed' => $l->t('%1$s changed the backup retention to %2$s', [$who, $p['policy'] ?? '']),
 					'snapshots_forgotten' => $l->t('%1$s moved %2$s snapshots of %3$s to the trash; they are deleted permanently after %4$s unless restored', [$who, $p['count'] ?? '', $p['target'] ?? '', $p['until'] ?? '']),
@@ -62,6 +70,8 @@ final class Notifier implements INotifier {
 					'catalog_trusted' => $l->t('%1$s accepted an older state of backup location %2$s (catalog generation %3$s)', [$who, $p['target'] ?? '', $p['generation'] ?? '']),
 					'slot_added' => $l->t('%1$s added backup passphrase slot %2$s (%3$s); download and confirm the new recovery kit', [$who, $p['slot'] ?? '', $p['label'] ?? '']),
 					'slot_replaced' => $l->t('%1$s set a new passphrase for backup key slot %2$s (%3$s); download and confirm the new recovery kit', [$who, $p['slot'] ?? '', $p['label'] ?? '']),
+					'user_export_retention_changed' => $l->t('%1$s changed how many exports per user are kept to %2$s', [$who, $p['keep'] ?? '']),
+					'user_exports_forgotten' => $l->t('%1$s removed %2$s per-user exports from %3$s', [$who, $p['count'] ?? '', $p['target'] ?? '']),
 					'slot_removed' => $l->t('%1$s removed backup passphrase slot %2$s; download and confirm the new recovery kit', [$who, $p['slot'] ?? '']),
 					default => $l->t('NG Backup security event'),
 				});

lib/Repository/BlobIndex.php

@@ -7,6 +7,7 @@ declare(strict_types=1);
 
 namespace OCA\NgBackup\Repository;
 
+use OCA\NgBackup\Backend\BackendException;
 use OCA\NgBackup\Backend\IBackend;
 use OCA\NgBackup\Crypto\StreamCipher;
 
@@ -25,9 +26,15 @@ final class BlobIndex {
 	private array $pending = [];
 
 	private ?IIndexCache $cache = null;
+	/** @var list<\Closure():void>|null cache writes held back by holdCache(), or null when writing directly */
+	private ?array $heldCacheWrites = null;
 	private string $repositoryId = '';
+	/** Index files written to the cache per database transaction while loading. */
+	private const CACHE_LOT = 256;
 	/** @var int index files downloaded by the last load() (for tests and diagnostics) */
 	public int $downloaded = 0;
+	/** @var array<string, true> packs whose index file is loaded (refresh() fetches only others) */
+	private array $loaded = [];
 
 	public function __construct(
 		private IBackend $backend,
@@ -40,52 +47,124 @@ final class BlobIndex {
 		$this->repositoryId = $repositoryId;
 	}
 
+	/**
+	 * Hold back cache writes until releaseCache(). The database dump reads inside a read-only
+	 * transaction on the same connection that the cache writes to: a write there fails on
+	 * PostgreSQL and would be rolled back with the dump transaction elsewhere.
+	 */
+	public function holdCache(): void {
+		$this->heldCacheWrites ??= [];
+	}
+
+	/** Write the cache changes held back since holdCache(). */
+	public function releaseCache(): void {
+		$writes = $this->heldCacheWrites ?? [];
+		$this->heldCacheWrites = null;
+		foreach ($writes as $write) {
+			$write();
+		}
+	}
+
+	/** @param list<array{id:string, offset:int, length:int, raw:int, flags:int}> $entries */
+	private function cachePut(string $packId, array $entries): void {
+		if ($this->heldCacheWrites !== null) {
+			$this->heldCacheWrites[] = function () use ($packId, $entries): void {
+				$this->cache?->put($this->repositoryId, $packId, $entries);
+			};
+			return;
+		}
+		$this->cache?->put($this->repositoryId, $packId, $entries);
+	}
+
+	/** @param list<string> $packIds */
+	private function cacheRemove(array $packIds): void {
+		if ($this->heldCacheWrites !== null) {
+			$this->heldCacheWrites[] = function () use ($packIds): void {
+				$this->cache?->remove($this->repositoryId, $packIds);
+			};
+			return;
+		}
+		$this->cache?->remove($this->repositoryId, $packIds);
+	}
+
 	/**
 	 * Load the index: one listing of index/, entries from the local cache where available,
 	 * and only the index files that are not cached yet are downloaded. Cached packs that no
 	 * longer exist on the backend are dropped from the cache.
 	 */
-	public function load(bool $verify = false): void {
-		$this->blobs = [];
+	public function load(bool $verify = false, ?callable $progress = null): void {
+		$hadIndex = $this->blobs !== [];
 		$cached = $verify ? [] : ($this->cache?->all($this->repositoryId) ?? []);
 		$present = [];
 		$this->downloaded = 0;
-		foreach ($this->backend->list('index') as $path) {
+		$order = []; // pack ids in listing order: where a blob is in two packs, the last listed wins
+		$fetch = [];
+		$known = array_keys($this->loaded + $cached + ($verify ? ($this->cache?->all($this->repositoryId) ?? []) : []));
+		foreach ($this->listIndex($known) as $path) {
 			$packId = basename($path);
 			$present[$packId] = true;
-			if (isset($cached[$packId])) {
-				$entries = $cached[$packId];
-			} else {
-				$fh = $this->backend->get($path);
-				$entries = json_decode($this->cipher->decryptString((string)stream_get_contents($fh), 'index:' . $packId), true, 512, JSON_THROW_ON_ERROR);
-				fclose($fh);
-				$this->downloaded++;
-				$this->cache?->put($this->repositoryId, $packId, $entries);
-			}
-			foreach ($entries as $e) {
-				$this->blobs[$e['id']] = [$packId, $e['offset'], $e['length'], $e['raw'], $e['flags']];
+			$order[] = $packId;
+			if (!isset($cached[$packId])) {
+				$fetch[] = $path;
 			}
 		}
-		if ($verify && $this->cache !== null) {
-			// Refresh the cache from what was just verified.
-			$this->cache->remove($this->repositoryId, array_keys($this->cache->all($this->repositoryId)));
-			foreach ($this->packs() as $packId => $_) {
-				$entries = [];
-				foreach ($this->blobs as $id => [$pack, $offset, $length, $raw, $flags]) {
-					if ($pack === $packId) {
-						$entries[] = ['id' => $id, 'offset' => $offset, 'length' => $length, 'raw' => $raw, 'flags' => $flags];
-					}
+		// only now: an empty listing that listIndex() refused leaves the index as it was
+		$this->blobs = [];
+		$this->loaded = $present;
+		// The rest is downloaded several at a time where the location allows it: on a large
+		// repository these are tens of thousands of small files. getMany() keeps their order, so
+		// the cached packs listed before each one are added first.
+		$next = 0;
+		$total = count($fetch);
+		$toCache = []; // written to the cache a few hundred at a time, each lot in one transaction
+		foreach ($this->backend->getMany($fetch) as $path => $data) {
+			$packId = basename($path);
+			$entries = json_decode($this->cipher->decryptString($data, 'index:' . $packId), true, 512, JSON_THROW_ON_ERROR);
+			$this->downloaded++;
+			if ($this->cache !== null) {
+				$toCache[$packId] = $entries;
+				// a check writes the whole cache afresh at the end
+				if (!$verify && count($toCache) >= self::CACHE_LOT) {
+					$this->cache->putMany($this->repositoryId, $toCache);
+					$toCache = [];
 				}
-				$this->cache->put($this->repositoryId, $packId, $entries);
 			}
+			for (; $next < count($order) && $order[$next] !== $packId; $next++) {
+				$this->add($order[$next], $cached[$order[$next]] ?? []);
+			}
+			$this->add($packId, $entries);
+			$next++;
+			if ($progress !== null) {
+				$progress($this->downloaded, $total);
+			}
+		}
+		for (; $next < count($order); $next++) {
+			$this->add($order[$next], $cached[$order[$next]] ?? []);
+		}
+		if ($verify && $this->cache !== null) {
+			// Refresh the cache from what was just verified, as the index files list it: a blob in
+			// two packs is in both rows, so that removing one of the packs leaves the other right.
+			// In one transaction: one row at a time took more than 6 minutes on a 1 TB repository
+			// (27,547 packs), long enough for the location to drop the connection.
+			$this->cache->replaceAll($this->repositoryId, $toCache);
 			return;
 		}
+		if ($toCache !== []) {
+			$this->cache?->putMany($this->repositoryId, $toCache);
+		}
 		$stale = array_keys(array_diff_key($cached, $present));
 		if ($stale !== []) {
 			$this->cache?->remove($this->repositoryId, $stale);
 		}
 	}
 
+	/** @param list<array{id:string, offset:int, length:int, raw:int, flags:int}> $entries */
+	private function add(string $packId, array $entries): void {
+		foreach ($entries as $e) {
+			$this->blobs[$e['id']] = [$packId, $e['offset'], $e['length'], $e['raw'], $e['flags']];
+		}
+	}
+
 	public function has(string $id): bool {
 		return isset($this->blobs[$id]) || isset($this->pending[$id]);
 	}
@@ -112,13 +191,81 @@ final class BlobIndex {
 		fwrite($stream, $this->cipher->encryptString(json_encode($entries, JSON_THROW_ON_ERROR), 'index:' . $packId));
 		rewind($stream);
 		$this->backend->put('index/' . $packId, $stream);
-		$this->cache?->put($this->repositoryId, $packId, $entries);
+		$this->cachePut($packId, $entries);
+		$this->loaded[$packId] = true;
 		foreach ($entries as $e) {
 			$this->blobs[$e['id']] = [$packId, $e['offset'], $e['length'], $e['raw'], $e['flags']];
 			unset($this->pending[$e['id']]);
 		}
 	}
 
+	/**
+	 * Add the index files that appeared on the location since load(), such as those of packs
+	 * another server's cleanup wrote while a restore runs. Only adds and updates: a blob is
+	 * never dropped, as a listing that misses files (a connection that failed) must not make a
+	 * restore lose blobs it knows. A blob in a new pack takes that pack's place.
+	 */
+	public function refresh(): void {
+		$fetch = [];
+		$listed = 0;
+		foreach ($this->listIndex(array_keys($this->loaded)) as $path) {
+			$listed++;
+			if (!isset($this->loaded[basename($path)])) {
+				$fetch[] = $path;
+			}
+		}
+		$toCache = [];
+		foreach ($this->backend->getMany($fetch) as $path => $data) {
+			$packId = basename($path);
+			/** @var list<array{id:string, offset:int, length:int, raw:int, flags:int}> $entries authenticated: written by NG Backup */
+			$entries = json_decode($this->cipher->decryptString($data, 'index:' . $packId), true, 512, JSON_THROW_ON_ERROR);
+			$this->downloaded++;
+			$this->add($packId, $entries);
+			$this->loaded[$packId] = true;
+			$toCache[$packId] = $entries;
+		}
+		if ($toCache !== []) {
+			$this->cache?->putMany($this->repositoryId, $toCache);
+		}
+	}
+
+	/**
+	 * The index files on the location. An empty listing while index files are known ($known,
+	 * pack ids) is usually a connection that failed quietly; taken as is, it would empty the
+	 * index and the cache, make a check report every blob missing, or make a cleanup wipe the
+	 * cache. So the connection is checked (the repository's config must be there) and the folder
+	 * listed once more. Empty again, three of the known index files are looked up one by one:
+	 * only when they are gone too is the repository taken as empty (another server removed its
+	 * last snapshot and cleaned up). Even when that is wrong, nothing on the location is lost:
+	 * only this index and the cache are empty until the next load.
+	 *
+	 * @param list<string> $known
+	 * @return list<string>
+	 * @throws BackendException when the location does not answer as it should
+	 */
+	private function listIndex(array $known): array {
+		$paths = $this->backend->listFiles('index');
+		if ($paths !== [] || $known === []) {
+			return $paths;
+		}
+		if (!$this->backend->exists('config')) {
+			throw new BackendException('The location listed no index files and has no repository config: not trusting that listing');
+		}
+		$paths = $this->backend->listFiles('index');
+		if ($paths !== []) {
+			return $paths;
+		}
+		// spread over the list: first, middle and last (another server's cleanup removes packs
+		// here and there, not in this order)
+		$n = count($known);
+		foreach (array_unique([$known[0], $known[intdiv($n, 2)], $known[$n - 1]]) as $packId) {
+			if ($this->backend->exists('index/' . $packId)) {
+				throw new BackendException('The location listed no index files, while index/' . $packId . ' is there: not trusting that listing');
+			}
+		}
+		return [];
+	}
+
 	/** @return array<string, list<array{id:string, offset:int, length:int}>> packId => blobs currently located in that pack */
 	public function packs(): array {
 		$packs = [];
@@ -131,7 +278,8 @@ final class BlobIndex {
 	/** Forget a pack: delete its index file and cache row. Blobs that now live elsewhere are kept. */
 	public function removePack(string $packId): void {
 		$this->backend->delete('index/' . $packId);
-		$this->cache?->remove($this->repositoryId, [$packId]);
+		$this->cacheRemove([$packId]);
+		unset($this->loaded[$packId]);
 		foreach ($this->blobs as $id => $loc) {
 			if ($loc[0] === $packId) {
 				unset($this->blobs[$id]);
@@ -139,6 +287,15 @@ final class BlobIndex {
 		}
 	}
 
+	/** Number of packs that hold blobs of the index. */
+	public function packCount(): int {
+		$packs = [];
+		foreach ($this->blobs as [$pack]) {
+			$packs[$pack] = true;
+		}
+		return count($packs);
+	}
+
 	/** Bytes of all blobs in the index (encrypted size, i.e. what is stored in packs). */
 	public function storedBytes(): int {
 		$total = 0;

lib/Repository/Catalog.php

@@ -28,6 +28,8 @@ final class Catalog {
 	public array $snapshots = [];
 	/** @var array<string, true> */
 	public array $trash = [];
+	/** @var array<string, true> manifest path => true, for a per-user export (users/<uid>/<exportId>) */
+	public array $userExports = [];
 	public string $hash = '';
 
 	public function __construct(
@@ -39,7 +41,7 @@ final class Catalog {
 	}
 
 	/** Load and verify the newest catalog; create the first one for repositories that have none. */
-	public function load(callable $listSnapshots, callable $listTrash): void {
+	public function load(callable $listSnapshots, callable $listTrash, callable $listUserExports): void {
 		$gens = $this->generations();
 		if ($gens === []) {
 			// First use (new or pre-catalog repository): adopt the current state as generation 1.
@@ -49,6 +51,7 @@ final class Catalog {
 			}
 			$this->snapshots = array_fill_keys($listSnapshots(), true);
 			$this->trash = array_fill_keys($listTrash(), true);
+			$this->userExports = array_fill_keys($listUserExports(), true);
 			$this->write();
 			return;
 		}
@@ -76,14 +79,23 @@ final class Catalog {
 		$this->hash = $hash;
 		$this->snapshots = array_fill_keys($data['snapshots'], true);
 		$this->trash = array_fill_keys($data['trash'], true);
+		// Catalogs written before user exports existed have no such key: default to empty rather
+		// than adopting the location's current users/ listing (that would skip verification).
+		$this->userExports = array_fill_keys($data['userExports'] ?? [], true);
 		$this->anchor?->set($this->repositoryId, $this->gen, $this->hash);
 	}
 
 	/** Write the next generation after the in-memory state was changed. */
 	public function write(): void {
 		$next = $this->gen + 1;
+		// Two writers starting from the same generation would otherwise overwrite each other
+		// silently and break the chain for whichever server anchored the lost write.
+		if ($this->backend->exists($this->path($next))) {
+			throw new RepositoryException("Catalog generation $next was written by another process at the same time; try again");
+		}
 		$plain = json_encode(['repository' => $this->repositoryId, 'gen' => $next, 'time' => gmdate('c'), 'prev' => $this->hash,
-			'snapshots' => array_keys($this->snapshots), 'trash' => array_keys($this->trash)], JSON_THROW_ON_ERROR);
+			'snapshots' => array_keys($this->snapshots), 'trash' => array_keys($this->trash),
+			'userExports' => array_keys($this->userExports)], JSON_THROW_ON_ERROR);
 		$encrypted = $this->cipher->encryptString($plain, $this->ad($next));
 		$stream = fopen('php://memory', 'w+b');
 		fwrite($stream, $encrypted);
@@ -116,7 +128,7 @@ final class Catalog {
 
 	/** @return list<int> */
 	private function generations(): array {
-		return array_map(fn ($p) => (int)basename($p), $this->backend->list('catalog'));
+		return array_map(fn ($p) => (int)basename($p), $this->backend->listFiles('catalog'));
 	}
 
 	private function path(int $gen): string {

lib/Repository/IIndexCache.php

@@ -15,6 +15,20 @@ interface IIndexCache {
 	/** @param list<array{id:string, offset:int, length:int, raw:int, flags:int}> $entries */
 	public function put(string $repositoryId, string $packId, array $entries): void;
 
+	/**
+	 * put() for many packs at once (one database transaction).
+	 *
+	 * @param array<string, list<array{id:string, offset:int, length:int, raw:int, flags:int}>> $packs packId => entries
+	 */
+	public function putMany(string $repositoryId, array $packs): void;
+
+	/**
+	 * Replace everything cached for the repository with $packs (one database transaction).
+	 *
+	 * @param array<string, list<array{id:string, offset:int, length:int, raw:int, flags:int}>> $packs packId => entries
+	 */
+	public function replaceAll(string $repositoryId, array $packs): void;
+
 	/** @param list<string> $packIds */
 	public function remove(string $repositoryId, array $packIds): void;
 }

lib/Repository/PackReader.php

@@ -0,0 +1,97 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\Repository;
+
+use OCA\NgBackup\Backend\IBackend;
+
+/**
+ * Reads blobs from packs. Restores and deep verifies read the blobs of a snapshot in the order
+ * they were written, so the stream of the pack read last is kept open and read on from where it
+ * is: one request per pack instead of one per blob (a round trip each, and on most remote
+ * storages a new connection or file handle too). Anything else opens the pack at the offset,
+ * as a single read always did.
+ *
+ * The open stream must not overlap other requests on the location (SFTP cannot read and write
+ * on one connection at once): Repository reaches the location through a PackReaderGuard, which
+ * closes it first.
+ */
+final class PackReader {
+	/** A gap up to this size in the open stream is read past instead of opening the pack again. */
+	private const SKIP_MAX = 8 * 1048576;
+	private const CHUNK = 1048576;
+
+	/** @var resource|null */
+	private $stream = null;
+	private string $pack = '';
+	private int $pos = 0;
+
+	public function __construct(
+		private IBackend $backend,
+	) {
+	}
+
+	public function read(string $pack, int $offset, int $length): string {
+		if ($this->stream !== null && $this->pack === $pack && $offset >= $this->pos && $offset - $this->pos <= self::SKIP_MAX) {
+			try {
+				$this->skipTo($offset);
+				return $this->readExactly($length);
+			} catch (\Exception) {
+				// The open stream broke (e.g. a timeout); open the pack again below.
+			}
+		}
+		$this->close();
+		$fh = $this->backend->get('packs/' . substr($pack, 0, 2) . '/' . $pack);
+		$this->stream = $fh;
+		$this->pack = $pack;
+		$this->pos = 0;
+		try {
+			if ($offset > 0 && (stream_get_meta_data($fh)['seekable'] ?? false) && fseek($fh, $offset) === 0) {
+				$this->pos = $offset;
+			}
+			$this->skipTo($offset); // a stream that cannot seek is read up to the offset
+			return $this->readExactly($length);
+		} catch (\Exception $e) {
+			$this->close();
+			throw $e;
+		}
+	}
+
+	public function close(): void {
+		$fh = $this->stream;
+		$this->stream = null;
+		if ($fh !== null) {
+			@fclose($fh);
+		}
+	}
+
+	public function __destruct() {
+		$this->close();
+	}
+
+	private function skipTo(int $offset): void {
+		while ($this->pos < $offset) {
+			$this->readExactly(min($offset - $this->pos, self::CHUNK));
+		}
+	}
+
+	/** Read $length bytes from the open stream; a short read closes it. */
+	private function readExactly(int $length): string {
+		$fh = $this->stream ?? throw new RepositoryException('No open pack stream');
+		$data = '';
+		while (strlen($data) < $length) {
+			$chunk = fread($fh, min($length - strlen($data), self::CHUNK));
+			if ($chunk === false || $chunk === '') {
+				$this->close();
+				throw new RepositoryException('Short read in pack ' . $this->pack);
+			}
+			$data .= $chunk;
+		}
+		$this->pos += $length;
+		return $data;
+	}
+}

lib/Repository/PackReaderGuard.php

@@ -0,0 +1,80 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\Repository;
+
+use OCA\NgBackup\Backend\IBackend;
+use OCA\NgBackup\Backend\IReadsAhead;
+
+/** The location as Repository sees it: closes the PackReader's open stream before every other request. */
+final class PackReaderGuard implements IBackend, IReadsAhead {
+	public function __construct(
+		private IBackend $inner,
+		private PackReader $reader,
+	) {
+	}
+
+	/** @param resource $stream */
+	public function put(string $path, $stream): void {
+		$this->reader->close();
+		$this->inner->put($path, $stream);
+	}
+
+	public function get(string $path) {
+		$this->reader->close();
+		return $this->inner->get($path);
+	}
+
+	public function getMany(array $paths): \Generator {
+		$this->reader->close();
+		return $this->inner->getMany($paths);
+	}
+
+	public function getRange(string $path, int $offset, int $length): string {
+		$this->reader->close();
+		return $this->inner->getRange($path, $offset, $length);
+	}
+
+	public function getRanges(array $ranges): \Generator {
+		$this->reader->close();
+		return $this->inner->getRanges($ranges);
+	}
+
+	public function canReadAhead(): bool {
+		return $this->inner instanceof IReadsAhead && $this->inner->canReadAhead();
+	}
+
+	/** Over connections of the location's own: the open stream may stay open. */
+	public function readAhead(array $ranges, string $spool): ?\Generator {
+		return $this->inner instanceof IReadsAhead ? $this->inner->readAhead($ranges, $spool) : null;
+	}
+
+	public function exists(string $path): bool {
+		$this->reader->close();
+		return $this->inner->exists($path);
+	}
+
+	public function move(string $from, string $to): void {
+		$this->reader->close();
+		$this->inner->move($from, $to);
+	}
+
+	public function list(string $prefix): array {
+		$this->reader->close();
+		return $this->inner->list($prefix);
+	}
+
+	public function listFiles(string $dir): array {
+		$this->reader->close();
+		return $this->inner->listFiles($dir);
+	}
+
+	public function delete(string $path): void {
+		$this->reader->close();
+		$this->inner->delete($path);
+	}
+}

lib/Repository/ReadAheadPlan.php

@@ -0,0 +1,123 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\Repository;
+
+/**
+ * The ranges of packs a restore reads, in order, for IReadsAhead::readAhead(), and the reading of
+ * blobs from them as the restore goes.
+ *
+ * add() takes the blobs in the order the restore needs them. A blob in the same pack as the range
+ * before it, not before that range and at most GAP after its end, extends that range; anything
+ * else starts a new one. read() takes the same blobs in the same order: a blob is in the current
+ * range or in the next one, which then becomes current; a blob not in the plan is read elsewhere.
+ */
+final class ReadAheadPlan {
+	/** Unused bytes between two blobs of a pack that are read along rather than asked for apart. */
+	public const GAP = 4 * 1048576;
+	/** Longest range: packs are 32 MiB, repacked ones too. */
+	public const MAX_RANGE = 64 * 1048576;
+	/** Ranges after the current one that read() looks in for a blob. */
+	private const SEARCH = 16;
+
+	/** @var list<array{0:string, 1:int, 2:int}> [path, offset, length] */
+	private array $ranges = [];
+	/** @var \Generator<int, resource|null>|null */
+	private ?\Generator $streams = null;
+	private int $current = -1;
+	/** @var resource|null */
+	private $stream = null;
+
+	/** @param string $spool local folder for the ranges read ahead (see IReadsAhead::readAhead()) */
+	public function __construct(
+		public readonly string $spool,
+	) {
+	}
+
+	public function add(string $path, int $offset, int $length): void {
+		$last = array_pop($this->ranges);
+		if ($last !== null) {
+			[$p, $start, $len] = $last;
+			if ($p === $path && $offset >= $start && $offset <= $start + $len + self::GAP
+				&& $offset + $length - $start <= self::MAX_RANGE) {
+				$this->ranges[] = [$p, $start, max($len, $offset + $length - $start)];
+				return;
+			}
+			$this->ranges[] = $last;
+		}
+		$this->ranges[] = [$path, $offset, $length];
+	}
+
+	/** @return list<array{0:string, 1:int, 2:int}> */
+	public function ranges(): array {
+		return $this->ranges;
+	}
+
+	/** @param \Generator<int, resource|null> $streams what IReadsAhead::readAhead() gave for ranges() */
+	public function readFrom(\Generator $streams): void {
+		$this->streams = $streams;
+	}
+
+	/** The bytes of a blob, or null when its range could not be read ahead (read it the usual way). */
+	public function read(string $path, int $offset, int $length): ?string {
+		if ($this->streams === null) {
+			return null;
+		}
+		if (!$this->contains($this->current, $path, $offset, $length)) {
+			// Normally the next range. Further on when blobs before it were read elsewhere: the
+			// index was reloaded after another server's cleanup moved them to new packs.
+			$to = null;
+			for ($i = $this->current + 1; $i <= $this->current + self::SEARCH && $to === null; $i++) {
+				if ($this->contains($i, $path, $offset, $length)) {
+					$to = $i;
+				}
+			}
+			if ($to === null) {
+				return null; // not where the plan has it
+			}
+			if ($this->current < 0) {
+				$this->streams->current();
+				$this->current = 0;
+			}
+			while ($this->current < $to) {
+				$this->streams->next();
+				$this->current++;
+			}
+			$stream = $this->streams->valid() ? $this->streams->current() : null;
+			$this->stream = is_resource($stream) ? $stream : null;
+		}
+		$fh = $this->stream;
+		if ($fh === null || fseek($fh, $offset - $this->ranges[$this->current][1]) !== 0) {
+			return null;
+		}
+		$data = '';
+		while (strlen($data) < $length) {
+			$chunk = fread($fh, $length - strlen($data));
+			if ($chunk === false || $chunk === '') {
+				return null;
+			}
+			$data .= $chunk;
+		}
+		return $data;
+	}
+
+	/** Ends the reads ahead, also halfway: closes their streams and connections. */
+	public function close(): void {
+		$this->stream = null;
+		$streams = $this->streams;
+		$this->streams = null;
+		unset($streams); // the generator's finally blocks run when it is destroyed
+	}
+
+	private function contains(int $i, string $path, int $offset, int $length): bool {
+		if ($i < 0 || !isset($this->ranges[$i])) {
+			return false;
+		}
+		[$p, $start, $len] = $this->ranges[$i];
+		return $p === $path && $offset >= $start && $offset + $length <= $start + $len;
+	}
+}

lib/Repository/Repository.php

@@ -9,6 +9,7 @@ namespace OCA\NgBackup\Repository;
 
 use OCA\NgBackup\Backend\BackendException;
 use OCA\NgBackup\Backend\IBackend;
+use OCA\NgBackup\Backend\IReadsAhead;
 use OCA\NgBackup\Crypto\KeyRing;
 use OCA\NgBackup\Crypto\StreamCipher;
 
@@ -28,12 +29,23 @@ final class Repository {
 	public const FORMAT = 1;
 	public const BLOB_SIZE = 4 * 1048576;
 	private const FLAG_DEFLATE = 1;
+	/** Blobs from this size on get a quick compression test before the full compression. */
+	private const DEFLATE_PROBE_FROM = 256 * 1024;
+	/** Bytes of each of the three slices (start, middle, end) in that test. */
+	private const DEFLATE_PROBE_SLICE = 32 * 1024;
+	/** Reads per blob in a deep verify before it is reported as unreadable (not corrupted). */
+	private const VERIFY_READ_ATTEMPTS = 3;
+	/** Largest read that loadBlobs() makes of blobs that follow each other in a pack. */
+	private const MERGED_READ_MAX = 16 * 1048576;
 
 	private StreamCipher $cipher;
 	private BlobIndex $index;
 	private ?PackWriter $runPacks = null;
 	private ?int $maxBytes = null;
 	private Catalog $catalog;
+	private PackReader $packReader;
+	/** verify() lists the pack folders from this many packs on (see presentPacks()); tests lower it. */
+	public int $listPacksAbove = 256;
 
 	private function __construct(
 		private IBackend $backend,
@@ -41,7 +53,9 @@ final class Repository {
 		private string $repositoryId,
 	) {
 		$this->cipher = new StreamCipher($keys);
-		$this->index = new BlobIndex($backend, $this->cipher);
+		$this->packReader = new PackReader($backend);
+		$this->backend = new PackReaderGuard($backend, $this->packReader);
+		$this->index = new BlobIndex($this->backend, $this->cipher);
 	}
 
 	public static function init(IBackend $backend, #[\SensitiveParameter] string $passphrase): self {
@@ -58,6 +72,14 @@ final class Repository {
 		if ($backend->exists('config')) {
 			throw new RepositoryException('A repository already exists at this location');
 		}
+		// No config, but backup data: the config is missing (or could not be seen just now, a
+		// connection that failed). A new repository here would write a config over the one that
+		// opens this data; refuse instead.
+		foreach (['index', 'snapshots', 'trash/snapshots', 'catalog'] as $dir) {
+			if ($backend->listFiles($dir) !== []) {
+				throw new RepositoryException("This location holds backup data ($dir/) but no repository config could be read: not creating a new repository over it. Check the connection and the folder; a missing config can be restored from the recovery kit.");
+			}
+		}
 		$id = bin2hex(random_bytes(16));
 		$config = ['format' => self::FORMAT, 'id' => $id, 'created' => gmdate('c'), 'key' => $wrappedKey,
 			'check' => base64_encode((new StreamCipher($keys))->encryptString($id, 'config-check'))];
@@ -68,7 +90,8 @@ final class Repository {
 	}
 
 	/** Open with the master key the server holds (scheduled backups, no passphrase needed). */
-	public static function openWithKey(IBackend $backend, KeyRing $keys, ?IIndexCache $cache = null, ?ICatalogAnchor $anchor = null): self {
+	/** @param ?callable(int, int): void $progress index files downloaded so far, and in all (see BlobIndex::load()) */
+	public static function openWithKey(IBackend $backend, KeyRing $keys, ?IIndexCache $cache = null, ?ICatalogAnchor $anchor = null, ?callable $progress = null): self {
 		$config = self::readConfig($backend);
 		try {
 			$ok = isset($config['check']) && (new StreamCipher($keys))->decryptString((string)base64_decode($config['check'], true), 'config-check') === $config['id'];
@@ -82,7 +105,7 @@ final class Repository {
 		if ($cache !== null) {
 			$repo->index->setCache($cache, $config['id']);
 		}
-		$repo->index->load();
+		$repo->index->load(false, $progress);
 		$repo->loadCatalog($anchor);
 		return $repo;
 	}
@@ -90,8 +113,9 @@ final class Repository {
 	private function loadCatalog(?ICatalogAnchor $anchor): void {
 		$this->catalog = new Catalog($this->backend, $this->cipher, $this->repositoryId, $anchor);
 		$this->catalog->load(
-			fn () => array_map('basename', $this->backend->list('snapshots')),
-			fn () => array_map('basename', $this->backend->list('trash/info')));
+			fn () => array_map('basename', $this->backend->listFiles('snapshots')),
+			fn () => array_map('basename', $this->backend->listFiles('trash/info')),
+			fn () => $this->backend->list('users'));
 	}
 
 	/** Refuse uploads that would make the stored data larger than this (null = no limit). */
@@ -189,17 +213,112 @@ final class Repository {
 		return ['snapshot' => $snapshotId] + $stats;
 	}
 
-	/** Restore a snapshot (or only paths starting with $prefix) into a local directory. */
-	public function restore(string $snapshotId, string $target, string $prefix = ''): int {
+	/**
+	 * Restore a snapshot (or only paths starting with $prefix) into a local directory. A $prefix
+	 * "dir/file/" also restores the file "dir/file" itself.
+	 *
+	 * @param bool $stripPrefix write "$target/<path without $prefix>" instead of
+	 *             "$target/<full logical path>" (disaster recovery: restoring e.g. "data/" or
+	 *             "config/" directly into the real data/config directory, not a subdirectory
+	 *             named after the prefix). Ignored when $prefix is '' (nothing to strip).
+	 * @param array<string, string>|null $skipped salvage: an array to collect the files that could
+	 *             not be read or decrypted (path => reason), which are then left out instead of
+	 *             stopping the restore; null (default) stops at the first such file
+	 * @param bool $keepUnchanged leave a file that is already in place with the size and
+	 *             modification time of the snapshot, as a backup takes such a file as unchanged:
+	 *             a restore that was stopped and runs again goes on where it was, without reading
+	 *             what it already restored from the location again
+	 */
+	public function restore(string $snapshotId, string $target, string $prefix = '', bool $stripPrefix = false, ?callable $heartbeat = null, ?array &$skipped = null, bool $keepUnchanged = false): int {
 		if ($prefix !== '' && !self::isSafePath(rtrim($prefix, '/'))) {
 			throw new RepositoryException('Invalid path prefix');
 		}
-		$count = 0;
-		foreach ($this->streamEntries($snapshotId) as $entry) {
-			if ($prefix !== '' && !str_starts_with($entry['p'], $prefix)) {
+		$plan = $this->readAhead($snapshotId, $prefix, $target, $stripPrefix, $keepUnchanged);
+		try {
+			return $this->restoreEntries($snapshotId, $target, $prefix, $stripPrefix, $heartbeat, $plan, $skipped, $keepUnchanged);
+		} finally {
+			$plan?->close();
+			if ($plan !== null) {
+				@rmdir($plan->spool);
+			}
+		}
+	}
+
+	/**
+	 * Start reading the packs of a restore ahead, when the location can (IReadsAhead): a first
+	 * pass over the snapshot lists the ranges of packs it needs, in order. The spool is a
+	 * folder in the target, which has room for the restore anyway.
+	 */
+	private function readAhead(string $snapshotId, string $prefix, string $target, bool $stripPrefix, bool $keepUnchanged): ?ReadAheadPlan {
+		if (!$this->backend instanceof IReadsAhead || !$this->backend->canReadAhead()) {
+			return null;
+		}
+		// what a restore that was stopped left behind: its files are unlinked once opened, but one
+		// that was being written when the process was killed stays (8 MiB, DR test 2026-11-05)
+		$stale = glob(rtrim($target, '/') . '/.ngb-restore-spool-*', GLOB_ONLYDIR);
+		foreach ($stale === false ? [] : $stale as $dir) {
+			if (is_link($dir)) {
+				continue;
+			}
+			$files = glob($dir . '/*');
+			foreach ($files === false ? [] : $files as $file) {
+				if (is_file($file) && !is_link($file)) {
+					@unlink($file);
+				}
+			}
+			@rmdir($dir);
+		}
+		$plan = new ReadAheadPlan(rtrim($target, '/') . '/.ngb-restore-spool-' . bin2hex(random_bytes(4)));
+		try {
+			foreach ($this->streamEntries($snapshotId) as $entry) {
+				if (!self::underPrefix($entry['p'], $prefix)) {
+					continue;
+				}
+				if ($keepUnchanged && self::inPlace(self::destination($target, $entry['p'], $prefix, $stripPrefix), $entry)) {
+					continue;
+				}
+				foreach ($entry['b'] as $id) {
+					try {
+						[$pack, $offset, $length] = $this->index->get($id);
+					} catch (RepositoryException) {
+						continue; // the restore reports it when it gets there
+					}
+					$plan->add('packs/' . substr($pack, 0, 2) . '/' . $pack, $offset, $length);
+				}
+			}
+		} catch (\Throwable) {
+			return null; // reading ahead is only faster: the restore itself reads the snapshot again and reports what is wrong
+		}
+		if (count($plan->ranges()) < 2 || (!is_dir($plan->spool) && !@mkdir($plan->spool, 0700, true))) {
+			return null;
+		}
+		try {
+			$streams = $this->backend->readAhead($plan->ranges(), $plan->spool);
+		} catch (\Throwable) {
+			$streams = null; // the usual reads report what is wrong
+		}
+		if ($streams === null) {
+			@rmdir($plan->spool);
+			return null;
+		}
+		$plan->readFrom($streams);
+		return $plan;
+	}
+
+	/** @param array<string, string>|null $skipped see restore() */
+	private function restoreEntries(string $snapshotId, string $target, string $prefix, bool $stripPrefix, ?callable $heartbeat, ?ReadAheadPlan $plan, ?array &$skipped, bool $keepUnchanged): int {
+		$count = 0;
+		$cleaned = [];
+		foreach ($this->streamEntries($snapshotId) as $entry) {
+			if (!self::underPrefix($entry['p'], $prefix)) {
+				continue;
+			}
+			$dest = self::destination($target, $entry['p'], $prefix, $stripPrefix);
+			if ($keepUnchanged && self::inPlace($dest, $entry)) {
+				// below the target as written by an earlier run of this restore (checked then)
+				$count++;
 				continue;
 			}
-			$dest = rtrim($target, '/') . '/' . $entry['p'];
 			if (!is_dir(dirname($dest))) {
 				mkdir(dirname($dest), 0700, true);
 			}
@@ -209,6 +328,10 @@ final class Repository {
 			if ($base === false || $dir === false || ($dir !== $base && !str_starts_with($dir, $base . '/')) || is_link($dest)) {
 				throw new RepositoryException('Refusing to write outside the restore directory: ' . $entry['p']);
 			}
+			if (!isset($cleaned[$dir])) {
+				self::removeStaleTemporaries($dir);
+				$cleaned[$dir] = true;
+			}
 			// Write next to the destination and rename after all blobs verified: at most one file
 			// is ever present twice.
 			$tmp = $dest . '.ngb-restore-' . bin2hex(random_bytes(6));
@@ -216,21 +339,87 @@ final class Repository {
 			if ($out === false) {
 				throw new RepositoryException('Cannot create a temporary file for ' . $entry['p']);
 			}
-			foreach ($entry['b'] as $id) {
-				fwrite($out, $this->loadBlob($id));
+			try {
+				foreach ($entry['b'] as $id) {
+					fwrite($out, $this->restoreBlob($id, $plan));
+					if ($heartbeat !== null) {
+						$heartbeat();
+					}
+				}
+				fclose($out);
+				clearstatcache(true, $tmp);
+				if (filesize($tmp) !== $entry['s']) {
+					throw new RepositoryException('Size mismatch restoring ' . $entry['p']);
+				}
+			} catch (RepositoryException|BackendException|\OCA\NgBackup\Crypto\CryptoException $e) {
+				// What the location gave back for this file is missing or damaged. Writing to the
+				// target (below) is not part of this: a full disk must still stop the restore.
+				if (is_resource($out)) {
+					fclose($out);
+				}
+				@unlink($tmp);
+				if ($skipped === null) {
+					throw $e;
+				}
+				$skipped[$entry['p']] = $e->getMessage();
+				continue;
 			}
-			fclose($out);
-			if (filesize($tmp) !== $entry['s']) {
-				unlink($tmp);
-				throw new RepositoryException('Size mismatch restoring ' . $entry['p']);
+			if (!rename($tmp, $dest)) {
+				@unlink($tmp);
+				throw new RepositoryException('Cannot put the restored file in place: ' . $entry['p']);
+			}
+			if (!touch($dest, $entry['m'])) {
+				throw new RepositoryException('Cannot set the modification time of ' . $entry['p']);
 			}
-			rename($tmp, $dest);
-			touch($dest, $entry['m']);
 			$count++;
 		}
 		return $count;
 	}
 
+	/** Where restore() writes the snapshot path $path. */
+	private static function destination(string $target, string $path, string $prefix, bool $stripPrefix): string {
+		$relPath = $path;
+		if ($stripPrefix && $prefix !== '') {
+			$relPath = $path === rtrim($prefix, '/') ? basename($path) : substr($path, strlen($prefix));
+		}
+		return rtrim($target, '/') . '/' . $relPath;
+	}
+
+	/**
+	 * A regular file (no link) at $dest with the size and modification time of the snapshot
+	 * entry: what a backup takes as unchanged, and what a finished restore of it leaves.
+	 *
+	 * @param array{s: int, m: int, ...} $entry
+	 */
+	private static function inPlace(string $dest, array $entry): bool {
+		clearstatcache(true, $dest);
+		return !is_link($dest) && is_file($dest) && filesize($dest) === $entry['s'] && filemtime($dest) === $entry['m'];
+	}
+
+	/** $prefix is "" (everything) or ends with "/"; the path without that "/" is a file to restore too. */
+	private static function underPrefix(string $path, string $prefix): bool {
+		return $prefix === '' || str_starts_with($path, $prefix) || $path === rtrim($prefix, '/');
+	}
+
+	/**
+	 * Remove what a restore that was stopped left in a directory this restore writes to:
+	 * "<name>.ngb-restore-<hex>" from here, ".<name>.ngb-restore-<hex>" from a restore through
+	 * Nextcloud. A files:scan would otherwise make them show up in Files.
+	 */
+	public static function removeStaleTemporaries(string $dir): void {
+		$names = scandir($dir);
+		foreach ($names === false ? [] : $names as $name) {
+			$path = $dir . '/' . $name;
+			if (self::isRestoreTemporary($name) && is_file($path) && !is_link($path)) {
+				@unlink($path);
+			}
+		}
+	}
+
+	public static function isRestoreTemporary(string $name): bool {
+		return preg_match('/.\.ngb-restore-[0-9a-f]{6}(?:[0-9a-f]{6})?$/', $name) === 1;
+	}
+
 	/**
 	 * Start writing a generated stream (e.g. a table dump) as blobs. Call flushPacks() when the
 	 * run is done, so the last pack is uploaded before anything references it.
@@ -243,6 +432,15 @@ final class Repository {
 		});
 	}
 
+	/** See BlobIndex::holdCache(): no database writes until releaseIndexCache(). */
+	public function holdIndexCache(): void {
+		$this->index->holdCache();
+	}
+
+	public function releaseIndexCache(): void {
+		$this->index->releaseCache();
+	}
+
 	public function flushPacks(): void {
 		$this->runPacks?->flush();
 	}
@@ -255,8 +453,8 @@ final class Repository {
 	 */
 	public function readLines(array $blobIds): \Generator {
 		$carry = '';
-		foreach ($blobIds as $id) {
-			$data = $carry . $this->loadBlob($id);
+		foreach ($this->loadBlobs($blobIds) as $blob) {
+			$data = $carry . $blob;
 			$lines = explode("\n", $data);
 			$carry = array_pop($lines);
 			yield from $lines;
@@ -279,6 +477,17 @@ final class Repository {
 	 * @param iterable<string> $lines
 	 */
 	public function writeSnapshot(string $snapshotId, array $meta, iterable $lines): void {
+		$this->putSnapshot($snapshotId, $meta, $lines);
+		$this->recordSnapshot($snapshotId);
+	}
+
+	/**
+	 * Store a snapshot object without touching the catalog. Use recordSnapshot() afterwards, from a
+	 * repository opened inside the catalog lock, so the catalog write builds on the latest generation.
+	 *
+	 * @param iterable<string> $lines
+	 */
+	public function putSnapshot(string $snapshotId, array $meta, iterable $lines): void {
 		$tree = fopen('php://temp/maxmemory:' . (4 * 1048576), 'w+b');
 		fwrite($tree, json_encode(['snapshot' => $snapshotId] + $meta, JSON_THROW_ON_ERROR) . "\n");
 		foreach ($lines as $line) {
@@ -292,6 +501,9 @@ final class Repository {
 		fclose($tree);
 		rewind($encrypted);
 		$this->backend->put('snapshots/' . $snapshotId, $encrypted);
+	}
+
+	public function recordSnapshot(string $snapshotId): void {
 		$this->catalog->snapshots[$snapshotId] = true;
 		$this->catalog->write();
 	}
@@ -349,31 +561,130 @@ final class Repository {
 			// must be decrypted and re-encrypted under the new path, not moved as raw bytes.
 			$dbInTrash = 'trash/' . $meta['db'];
 			$this->putObject($dbInTrash, $this->getObject($meta['db']));
-			$this->backend->delete($meta['db']);
 		}
-		// The snapshot object is bound to its id (not its path), so it can be moved as raw bytes.
-		$this->backend->move('snapshots/' . $snapshotId, 'trash/snapshots/' . $snapshotId);
+		// Copy first, switch the catalog, delete the originals last: a crash at any point leaves
+		// either the old state or the new one plus unreferenced leftovers, never a catalog entry
+		// pointing at a missing object. The snapshot object is bound to its id (not its path),
+		// so it can be copied as raw bytes.
+		$this->copyRaw('snapshots/' . $snapshotId, 'trash/snapshots/' . $snapshotId);
 		$this->putObject('trash/info/' . $snapshotId, json_encode(['forgottenAt' => time(), 'by' => $by, 'db' => $meta['db'] ?? null,
 			'dbInTrash' => $dbInTrash, 'time' => $meta['time'] ?? null, 'label' => $meta['label'] ?? ''], JSON_THROW_ON_ERROR));
 		unset($this->catalog->snapshots[$snapshotId]);
 		$this->catalog->trash[$snapshotId] = true;
 		$this->catalog->write();
+		if ($dbInTrash !== null) {
+			$this->backend->delete($meta['db']);
+		}
+		$this->backend->delete('snapshots/' . $snapshotId);
 	}
 
 	/** Undo forget(): move a snapshot back from the trash. */
 	public function untrash(string $snapshotId): void {
 		$info = $this->trashInfo($snapshotId);
-		if ($info['dbInTrash'] !== null && $this->backend->exists($info['dbInTrash'])) {
+		$restoreDb = $info['dbInTrash'] !== null && $this->backend->exists($info['dbInTrash']);
+		if ($restoreDb) {
 			$this->putObject($info['db'], $this->getObject($info['dbInTrash']));
-			$this->backend->delete($info['dbInTrash']);
 		}
-		$this->backend->move('trash/snapshots/' . $snapshotId, 'snapshots/' . $snapshotId);
+		// Same order as forget(): copy, switch the catalog, then delete the trash copies.
+		$this->copyRaw('trash/snapshots/' . $snapshotId, 'snapshots/' . $snapshotId);
 		$this->catalog->snapshots[$snapshotId] = true;
 		unset($this->catalog->trash[$snapshotId]);
 		$this->catalog->write();
+		if ($restoreDb) {
+			$this->backend->delete($info['dbInTrash']);
+		}
+		$this->backend->delete('trash/snapshots/' . $snapshotId);
 		$this->backend->delete('trash/info/' . $snapshotId);
 	}
 
+	/** Copy an object as raw bytes, buffered locally (remote read streams cannot be uploaded directly everywhere). */
+	private function copyRaw(string $from, string $to): void {
+		$in = $this->backend->get($from);
+		$buffer = fopen('php://temp/maxmemory:' . (4 * 1048576), 'w+b');
+		if ($buffer === false) {
+			fclose($in);
+			throw new RepositoryException("Cannot buffer $from");
+		}
+		try {
+			if (stream_copy_to_stream($in, $buffer) === false) {
+				throw new RepositoryException("Cannot read $from");
+			}
+		} finally {
+			fclose($in);
+		}
+		rewind($buffer);
+		$this->backend->put($to, $buffer);
+	}
+
+	/** Record a user_migration export's manifest in the catalog (rollback-protected like a snapshot). */
+	public function recordUserExport(string $manifestPath): void {
+		$this->catalog->userExports[$manifestPath] = true;
+		$this->catalog->write();
+	}
+
+	/**
+	 * User export manifests according to the verified catalog, newest first. A manifest the
+	 * catalog lists but the location no longer has means it was deleted or hidden behind NG
+	 * Backup's back, same as a missing snapshot (see listSnapshots()).
+	 *
+	 * @return list<string>
+	 */
+	public function listUserExports(?string $uid = null): array {
+		$prefix = $uid !== null ? 'users/' . $uid . '/' : 'users/';
+		$out = [];
+		foreach (array_keys($this->catalog->userExports) as $path) {
+			if (!str_starts_with($path, $prefix)) {
+				continue;
+			}
+			if (!$this->backend->exists($path)) {
+				throw new RepositoryException("User export $path is missing on the location (deleted or hidden outside NG Backup)");
+			}
+			$out[] = $path;
+		}
+		sort($out, SORT_STRING);
+		return array_reverse($out);
+	}
+
+	/** Whether $manifestPath is a user export the verified catalog actually recorded. */
+	public function isRecordedUserExport(string $manifestPath): bool {
+		return isset($this->catalog->userExports[$manifestPath]);
+	}
+
+	/**
+	 * The recorded export $ref names: a manifest path (users/<uid>/<exportId>) as is, or a bare
+	 * user id (also "users/<uid>") when that user has exactly one export here. Anything else
+	 * throws, with the exports to choose from in the message.
+	 */
+	public function resolveUserExport(string $ref): string {
+		if ($this->isRecordedUserExport($ref)) {
+			return $ref;
+		}
+		$rest = trim($ref, '/');
+		if (str_starts_with($rest, 'users/')) {
+			$rest = substr($rest, strlen('users/'));
+		}
+		$uid = explode('/', $rest)[0];
+		$exports = $uid !== '' ? $this->listUserExports($uid) : [];
+		if (!str_contains($rest, '/') && count($exports) === 1) {
+			return $exports[0];
+		}
+		if ($exports === []) {
+			throw new RepositoryException("$ref is not a recorded user export for this location, and $uid has no exports here. Expected users/<uid>/<exportId>; occ backup:user:list shows the exports");
+		}
+		$which = str_contains($rest, '/') ? "$ref is not a recorded user export for this location" : "$uid has " . count($exports) . ' exports here';
+		throw new RepositoryException("$which; pass one of these (newest first):\n  " . implode("\n  ", $exports));
+	}
+
+	/** Permanently delete a user export. Its blobs are freed by the next prune() like any other. */
+	public function forgetUserExport(string $manifestPath): void {
+		if (!isset($this->catalog->userExports[$manifestPath])) {
+			throw new RepositoryException("$manifestPath is not a recorded user export");
+		}
+		unset($this->catalog->userExports[$manifestPath]);
+		$this->catalog->write();
+		$this->backend->delete($manifestPath);
+	}
+
 	/** @return array<string, array{forgottenAt:int, by:string, db:?string, dbInTrash:?string, time:?string, label:string}> */
 	public function trash(): array {
 		$out = [];
@@ -389,23 +700,26 @@ final class Repository {
 
 	/** Permanently delete trash entries older than $delaySeconds. @return list<string> purged snapshot ids */
 	public function purgeTrash(int $delaySeconds): array {
-		$purged = [];
+		$doomed = [];
 		foreach ($this->trash() as $id => $info) {
 			if (time() - $info['forgottenAt'] < $delaySeconds) {
 				continue;
 			}
+			$doomed[$id] = $info;
+			unset($this->catalog->trash[$id]);
+		}
+		if ($doomed === []) {
+			return [];
+		}
+		$this->catalog->write();
+		foreach ($doomed as $id => $info) {
 			if ($info['dbInTrash'] !== null) {
 				$this->backend->delete($info['dbInTrash']);
 			}
 			$this->backend->delete('trash/snapshots/' . $id);
 			$this->backend->delete('trash/info/' . $id);
-			unset($this->catalog->trash[$id]);
-			$purged[] = $id;
 		}
-		if ($purged !== []) {
-			$this->catalog->write();
-		}
-		return $purged;
+		return array_keys($doomed);
 	}
 
 	private function trashInfo(string $snapshotId): array {
@@ -457,7 +771,10 @@ final class Repository {
 				}
 			}
 		}
-		foreach ($this->backend->list('users') as $path) {
+		// listUserExports() throws when a recorded export's manifest is missing: then stop, since
+		// freeing its blobs would turn a tampering or storage alarm into irreversible deletion.
+		$exports = array_unique(array_merge($this->listUserExports(), $this->backend->list('users')));
+		foreach ($exports as $path) {
 			foreach (json_decode($this->getObject($path), true, 512, JSON_THROW_ON_ERROR)['entries'] as $e) {
 				foreach ($e['b'] ?? [] as $b) {
 					$used[$b] = true;
@@ -521,7 +838,7 @@ final class Repository {
 	 * @return list<string>
 	 */
 	public function listSnapshots(): array {
-		$present = array_flip(array_map('basename', $this->backend->list('snapshots')));
+		$present = array_flip(array_map('basename', $this->backend->listFiles('snapshots')));
 		$listed = array_keys($this->catalog->snapshots);
 		foreach ($listed as $id) {
 			if (!isset($present[$id])) {
@@ -574,7 +891,7 @@ final class Repository {
 		}
 		$flags = 0;
 		$payload = $data;
-		$deflated = gzdeflate($data, 6);
+		$deflated = self::worthDeflating($data) ? gzdeflate($data, 6) : false;
 		if ($deflated !== false && strlen($deflated) < strlen($data) * 0.95) {
 			$payload = $deflated;
 			$flags |= self::FLAG_DEFLATE;
@@ -584,9 +901,167 @@ final class Repository {
 		return $id;
 	}
 
+	/**
+	 * Photos, video and archives are compressed already: deflating them takes most of a backup's
+	 * CPU time (about 24 MiB/s) only to be thrown away, as it saves less than the 5% that keeps
+	 * it. A fast deflate of three small slices tells first; below 10% savings there, the full
+	 * deflate is skipped.
+	 */
+	private static function worthDeflating(string $data): bool {
+		$n = strlen($data);
+		if ($n < self::DEFLATE_PROBE_FROM) {
+			return true;
+		}
+		$k = self::DEFLATE_PROBE_SLICE;
+		$probe = substr($data, 0, $k) . substr($data, intdiv($n - $k, 2), $k) . substr($data, $n - $k);
+		$deflated = gzdeflate($probe, 1);
+		return $deflated !== false && strlen($deflated) * 10 < strlen($probe) * 9;
+	}
+
+	/**
+	 * Blobs spread over many packs (the tree segments of a run, one per step), through
+	 * IBackend::getRanges(): on a remote location one at a time is a round trip each, which for
+	 * a long run made writing its snapshot take a quarter of an hour. Blobs that follow each
+	 * other in a pack are read as one range.
+	 *
+	 * @param list<string> $ids
+	 * @return \Generator<int, string> verified blob contents, in order
+	 */
+	private function loadBlobs(array $ids): \Generator {
+		/** @var list<array{0:string, 1:int, 2:int}> $ranges [path, offset, length] of each read */
+		$ranges = [];
+		/** @var list<list<array{0:string, 1:int, 2:int}>> $parts per read: [blob id, offset in the read, length] */
+		$parts = [];
+		// the read being extended
+		$curPath = null;
+		$curOffset = 0;
+		$curLength = 0;
+		$curParts = [];
+		foreach ($ids as $id) {
+			[$pack, $offset, $length] = $this->index->get($id);
+			$path = 'packs/' . substr($pack, 0, 2) . '/' . $pack;
+			if ($curPath === $path && $curOffset + $curLength === $offset && $curLength + $length <= self::MERGED_READ_MAX) {
+				$curParts[] = [$id, $curLength, $length];
+				$curLength += $length;
+				continue;
+			}
+			if ($curPath !== null) {
+				$ranges[] = [$curPath, $curOffset, $curLength];
+				$parts[] = $curParts;
+			}
+			[$curPath, $curOffset, $curLength, $curParts] = [$path, $offset, $length, [[$id, 0, $length]]];
+		}
+		if ($curPath !== null) {
+			$ranges[] = [$curPath, $curOffset, $curLength];
+			$parts[] = $curParts;
+		}
+		$done = 0;
+		try {
+			foreach ($this->backend->getRanges($ranges) as $i => $data) {
+				foreach ($parts[$i] as [$id, $at, $length]) {
+					try {
+						$blob = $this->decodeBlob($id, substr($data, $at, $length));
+					} catch (\Exception) {
+						// a read that went wrong on the way (see loadBlob()): this blob on its own
+						$blob = $this->loadBlob($id);
+						// its pack stream is closed before the next range is read on the same connection
+						$this->packReader->close();
+					}
+					yield $blob;
+					$done++;
+				}
+			}
+		} catch (BackendException) {
+			// A pack moved, or the read failed for a while (see loadBlob()): the rest one blob at a
+			// time, each read once more after a failure.
+			foreach (array_slice($ids, $done) as $id) {
+				yield $this->loadBlob($id);
+			}
+		}
+	}
+
+	/** A blob for restore(): read ahead when it could be, otherwise (or when that copy is bad) the usual way. */
+	private function restoreBlob(string $id, ?ReadAheadPlan $plan): string {
+		if ($plan !== null) {
+			[$pack, $offset, $length] = $this->index->get($id);
+			$encrypted = $plan->read('packs/' . substr($pack, 0, 2) . '/' . $pack, $offset, $length);
+			if ($encrypted !== null) {
+				try {
+					return $this->decodeBlob($id, $encrypted);
+				} catch (\Exception) {
+					// read again from the location below, which reports what is wrong
+				}
+			}
+		}
+		return $this->loadBlob($id);
+	}
+
 	private function loadBlob(string $id): string {
-		[$pack, $offset, $length, $raw, $flags] = $this->index->get($id);
-		$encrypted = $this->backend->getRange('packs/' . substr($pack, 0, 2) . '/' . $pack, $offset, $length);
+		[$pack, $offset, $length] = $this->index->get($id);
+		try {
+			$encrypted = $this->packReader->read($pack, $offset, $length);
+		} catch (BackendException $e) {
+			// Another server's cleanup may have repacked this blob into a new pack since the index
+			// was loaded (a disaster recovery test while the original server still runs): add the
+			// new index files, and read the blob where it is now. Or the read failed for a while
+			// (a connection that died; the backend has replaced it by now): then read it once
+			// more where it was. A second failure is the real one.
+			try {
+				$this->index->refresh();
+			} catch (\Throwable) {
+				// the location could not be listed either: read again where the blob was
+			}
+			[$moved, $offset, $length] = $this->index->get($id);
+			try {
+				$encrypted = $this->packReader->read($moved, $offset, $length);
+			} catch (BackendException) {
+				throw $e;
+			}
+			$pack = $moved;
+		}
+		try {
+			return $this->decodeBlob($id, $encrypted);
+		} catch (\Exception $damaged) {
+			// Bytes that do not decrypt: damaged on the location, or a read that went wrong on the
+			// way (a stream that lost its place: an SMB restore stopped after 17 hours like this).
+			// Read exactly this blob once more, on a request of its own; only a second failure
+			// means the data itself is damaged.
+			$this->packReader->close();
+			try {
+				$again = $this->backend->getRange('packs/' . substr($pack, 0, 2) . '/' . $pack, $offset, $length);
+			} catch (\Exception) {
+				throw $damaged;
+			}
+			$data = $this->decodeBlob($id, $again);
+			if (function_exists('OCP\Log\logger')) {
+				\OCP\Log\logger('ng_backup')->warning('NG Backup: blob ' . $id . ' did not decrypt as first read from pack ' . $pack . ' at ' . $offset . '; read again, it is fine. First read: ' . self::howItDiffered($encrypted, $again));
+			}
+			return $data;
+		}
+	}
+
+	/**
+	 * What a read that went wrong looked like next to the right bytes, for the log: where it starts
+	 * to differ, and whether the rest is zeros or the right bytes from another place (a stream that
+	 * lost its place).
+	 */
+	private static function howItDiffered(string $wrong, string $right): string {
+		$at = strspn($wrong ^ $right, "\0");
+		$text = strlen($wrong) . ' bytes, differ from byte ' . $at . ' of ' . strlen($right);
+		$tail = substr($wrong, $at, 64);
+		if ($tail === '') {
+			return $text . ' (too short)';
+		}
+		if (trim($tail, "\0") === '') {
+			return $text . ' (zeros)';
+		}
+		$found = strpos($right, $tail);
+		return $text . ($found !== false ? ' (the right bytes from ' . ($found - $at) . ' bytes further on)' : ' (other bytes)');
+	}
+
+	/** Decrypts and checks a blob read from its pack; throws when it is corrupted or tampered with. */
+	private function decodeBlob(string $id, string $encrypted): string {
+		[, , , $raw, $flags] = $this->index->get($id);
 		$payload = $this->cipher->decryptString($encrypted, 'blob:' . $id);
 		$data = ($flags & self::FLAG_DEFLATE) ? gzinflate($payload) : $payload;
 		if ($data === false || strlen($data) !== $raw || $this->keys->blobId($data) !== $id) {
@@ -609,6 +1084,184 @@ final class Repository {
 		return $this->streamEntries($snapshotId);
 	}
 
+	/**
+	 * Checksum audit of a snapshot: every blob it references (files and the database dump, when
+	 * the snapshot has one) must be in the index, freshly re-downloaded and re-authenticated from
+	 * the location rather than trusted from the local cache (same reasoning as prune()), and its
+	 * pack must still be present. With $deep, each blob is also downloaded and decrypted, which
+	 * verifies its AEAD authentication tag and its content hash against the blob id (loadBlob()
+	 * already does both on every real read -- this just does it for everything in the snapshot,
+	 * deliberately, rather than relying on it to come up during a later restore). A blob
+	 * referenced by more than one file is only checked once; a missing database manifest is a
+	 * failure, not something to silently skip over.
+	 *
+	 * @param ?callable(array{phase:string, done:int, total:?int, blobs?:int, bytes?:int}):void $heartbeat
+	 *        called often during the check, with how far it is: phase "index" (index files
+	 *        downloaded), "packs" (pack folders listed), "files" and "database" (files of the
+	 *        snapshot checked); callers use it to keep a time-boxed lease alive and to report
+	 * @return array{filesChecked:int, blobsChecked:int, bytesChecked:int, missing:list<string>, failed:list<string>, unreadable:list<string>, readError:string}
+	 */
+	public function verify(string $snapshotId, bool $deep = false, ?callable $heartbeat = null): array {
+		$heartbeat ??= static function (array $progress): void {
+		};
+		$meta = $this->snapshotMeta($snapshotId);
+		$filesTotal = isset($meta['stats']['files']) ? (int)$meta['stats']['files'] : null;
+		$this->index->load(true, static function (int $done, int $total) use ($heartbeat): void {
+			$heartbeat(['phase' => 'index', 'done' => $done, 'total' => $total]);
+		});
+		$stats = ['filesChecked' => 0, 'blobsChecked' => 0, 'bytesChecked' => 0, 'missing' => [], 'failed' => [], 'unreadable' => [], 'readError' => ''];
+		$seen = [];
+		[$packSeen, $listedDirs] = $this->presentPacks($heartbeat);
+		foreach ($this->streamEntries($snapshotId) as $entry) {
+			$stats['filesChecked']++;
+			foreach ($entry['b'] as $id) {
+				if (isset($seen[$id])) {
+					continue;
+				}
+				$seen[$id] = true;
+				$this->verifyBlob($id, $deep, $stats, $packSeen, $listedDirs);
+				$heartbeat(['phase' => 'files', 'done' => $stats['filesChecked'], 'total' => $filesTotal,
+					'blobs' => $stats['blobsChecked'], 'bytes' => $stats['bytesChecked']]);
+			}
+		}
+		if (isset($meta['db']) && is_string($meta['db'])) {
+			if (!$this->backend->exists($meta['db'])) {
+				$stats['missing'][] = $meta['db'];
+			} else {
+				$dbManifest = json_decode($this->getObject($meta['db']), true, 512, JSON_THROW_ON_ERROR);
+				foreach ($dbManifest['tables'] as $info) {
+					foreach ($info['blobs'] as $id) {
+						if (isset($seen[$id])) {
+							continue;
+						}
+						$seen[$id] = true;
+						$this->verifyBlob($id, $deep, $stats, $packSeen, $listedDirs);
+						$heartbeat(['phase' => 'database', 'done' => $stats['filesChecked'], 'total' => $filesTotal,
+							'blobs' => $stats['blobsChecked'], 'bytes' => $stats['bytesChecked']]);
+					}
+				}
+			}
+		}
+		return $stats;
+	}
+
+	/**
+	 * Which packs are on the location, from one listing per pack folder instead of a request per
+	 * pack. A folder that cannot be listed, or comes back empty (which a storage also reports when
+	 * it could not look), is left out: its packs are then checked one by one. With no more packs
+	 * than folders nothing is listed: a request per pack is fewer requests then, and on FTP every
+	 * request takes a data connection, of which a server may have only a few.
+	 *
+	 * @return array{0: array<string, bool>, 1: array<string, true>} pack id => present, and the
+	 *                                                              folders that were listed
+	 */
+	private function presentPacks(callable $heartbeat): array {
+		$present = [];
+		$listed = [];
+		if ($this->index->packCount() <= $this->listPacksAbove) {
+			return [$present, $listed];
+		}
+		for ($i = 0; $i < 256; $i++) {
+			$dir = sprintf('%02x', $i);
+			try {
+				$files = $this->backend->listFiles('packs/' . $dir);
+			} catch (BackendException) {
+				$files = [];
+			}
+			foreach ($files as $path) {
+				$present[basename($path)] = true;
+			}
+			if ($files !== []) {
+				$listed[$dir] = true;
+			}
+			$heartbeat(['phase' => 'packs', 'done' => $i + 1, 'total' => 256]);
+		}
+		return [$present, $listed];
+	}
+
+	/**
+	 * Same checks as verify(), for a user export: every blob its manifest references must be in
+	 * the freshly re-authenticated index with its pack present; $deep also decrypts each.
+	 *
+	 * @return array{filesChecked:int, blobsChecked:int, bytesChecked:int, missing:list<string>, failed:list<string>, unreadable:list<string>, readError:string}
+	 */
+	public function verifyUserExport(string $manifestPath, bool $deep = false, ?callable $heartbeat = null): array {
+		if (!$this->isRecordedUserExport($manifestPath)) {
+			throw new RepositoryException("$manifestPath is not a recorded user export for this location");
+		}
+		$heartbeat ??= static function (array $progress): void {
+		};
+		$this->index->load(true, static function (int $done, int $total) use ($heartbeat): void {
+			$heartbeat(['phase' => 'index', 'done' => $done, 'total' => $total]);
+		});
+		$stats = ['filesChecked' => 0, 'blobsChecked' => 0, 'bytesChecked' => 0, 'missing' => [], 'failed' => [], 'unreadable' => [], 'readError' => ''];
+		$seen = [];
+		$packSeen = [];
+		$manifest = json_decode($this->getObject($manifestPath), true, 512, JSON_THROW_ON_ERROR);
+		foreach ($manifest['entries'] as $entry) {
+			if (($entry['t'] ?? '') !== 'f') {
+				continue;
+			}
+			$stats['filesChecked']++;
+			foreach ($entry['b'] ?? [] as $id) {
+				if (isset($seen[$id])) {
+					continue;
+				}
+				$seen[$id] = true;
+				$this->verifyBlob($id, $deep, $stats, $packSeen);
+				$heartbeat(['phase' => 'files', 'done' => $stats['filesChecked'], 'total' => null,
+					'blobs' => $stats['blobsChecked'], 'bytes' => $stats['bytesChecked']]);
+			}
+		}
+		return $stats;
+	}
+
+	/**
+	 * @param array<string, bool> $packSeen pack id => present; filled in as packs are checked
+	 * @param array<string, true> $listedDirs pack folders whose listing is in $packSeen: a pack
+	 *                                        not in it is not there
+	 */
+	private function verifyBlob(string $id, bool $deep, array &$stats, array &$packSeen, array $listedDirs = []): void {
+		if (!$this->index->has($id)) {
+			$stats['missing'][] = $id;
+			return;
+		}
+		[$pack] = $this->index->get($id);
+		$packExists = $packSeen[$pack] ??= isset($listedDirs[substr($pack, 0, 2)])
+			? false
+			: $this->backend->exists('packs/' . substr($pack, 0, 2) . '/' . $pack);
+		if (!$packExists) {
+			$stats['missing'][] = $id;
+			return;
+		}
+		$stats['blobsChecked']++;
+		if (!$deep) {
+			return;
+		}
+		// Reading and checking are kept apart: a read that fails is usually a network or
+		// storage error, so it is retried and reported as unreadable (a pack that stays
+		// unreadable may still be truncated). Only a blob that was read but does not
+		// decrypt or match its id counts as failed: that is proof of damage.
+		[, $offset, $length] = $this->index->get($id);
+		$encrypted = null;
+		for ($attempt = 1; $attempt <= self::VERIFY_READ_ATTEMPTS && $encrypted === null; $attempt++) {
+			try {
+				$encrypted = $this->packReader->read($pack, $offset, $length);
+			} catch (\Exception $e) { // storage adapters throw their own exceptions; \Error (a bug) is not retried
+				$stats['readError'] = $e->getMessage();
+			}
+		}
+		if ($encrypted === null) {
+			$stats['unreadable'][] = $id;
+			return;
+		}
+		try {
+			$stats['bytesChecked'] += strlen($this->decodeBlob($id, $encrypted));
+		} catch (\Exception) { // damage; an \Error is a bug and must not be reported as damage
+			$stats['failed'][] = $id;
+		}
+	}
+
 	/** The meta record (first line) of a snapshot. */
 	public function snapshotMeta(string $snapshotId): array {
 		$plain = fopen('php://temp/maxmemory:' . (4 * 1048576), 'w+b');

lib/Service/AlertService.php

@@ -54,6 +54,13 @@ final class AlertService {
 			['kind' => $run->getKind(), 'target' => $targetName, 'error' => mb_strimwidth((string)$run->getError(), 0, 300, '…')]);
 	}
 
+	/** A backup that finished but is missing unreadable files, or holds files that changed while read. */
+	public function runWarnings(Run $run, string $targetName, int $unreadable, int $changing, array $examples): void {
+		$this->notifyAdmins('run_warnings', 'run-' . $run->getId(), ['target' => $targetName,
+			'unreadable' => (string)$unreadable, 'changing' => (string)$changing,
+			'examples' => mb_strimwidth(implode(', ', array_merge($examples['unreadable'], $examples['changing'])), 0, 300, '…')]);
+	}
+
 	/**
 	 * Remember how much is stored on a location (for the settings page) and warn administrators
 	 * once a day when it is at 80% of its limit or more.
@@ -97,7 +104,7 @@ final class AlertService {
 		}
 		$this->appConfig->setValueString(Application::APP_ID, $key, date('Y-m-d'));
 		$this->notifyAdmins('backup_stale', 'stale-' . $target->getId() . '-' . date('Y-m-d'),
-			['target' => $target->getName(), 'since' => $last ? date('Y-m-d H:i', $lastTime) : 'never']);
+			['target' => $target->getName(), 'since' => $last ? date('Y-m-d H:i', $lastTime) : '']);
 	}
 
 	private function notifyAdmins(string $subject, string $objectId, array $params): void {

lib/Service/BackupService.php

@@ -14,8 +14,12 @@ use OCA\NgBackup\Db\Snapshot;
 use OCA\NgBackup\Db\SnapshotMapper;
 use OCA\NgBackup\Db\Target;
 use OCA\NgBackup\Job\BackupRun;
+use OCA\NgBackup\Repository\Repository;
+use OCA\NgBackup\Repository\RepositoryException;
+use OCP\AppFramework\Db\DoesNotExistException;
 use OCP\App\IAppManager;
 use OCP\IConfig;
+use OCP\DB\QueryBuilder\IQueryBuilder;
 use OCP\IDBConnection;
 use OCP\Lock\ILockingProvider;
 use OCP\Lock\LockedException;
@@ -30,6 +34,11 @@ use Psr\Log\LoggerInterface;
  */
 final class BackupService {
 	public const KIND_FULL = 'full';
+	/** Characters of a snapshot label (the column holds 255) */
+	public const LABEL_MAX = 100;
+
+	/** @var \WeakMap<Repository, string> the location settings each kept repository was opened with */
+	private \WeakMap $openedWith;
 
 	public function __construct(
 		private TargetService $targets,
@@ -44,9 +53,16 @@ final class BackupService {
 		private AlertService $alerts,
 		private LeaseService $leases,
 	) {
+		/** @var \WeakMap<Repository, string> $opened */
+		$opened = new \WeakMap();
+		$this->openedWith = $opened;
 	}
 
 	public function start(Target $target, string $label = ''): Run {
+		$label = trim($label);
+		if (mb_strlen($label) > self::LABEL_MAX) {
+			throw new \InvalidArgumentException('A label has at most ' . self::LABEL_MAX . ' characters');
+		}
 		if (!$this->keys->everConfirmed()) {
 			throw new \RuntimeException('Confirm the recovery kit first (occ backup:key:confirm)');
 		}
@@ -67,6 +83,46 @@ final class BackupService {
 		}
 	}
 
+	/**
+	 * The expected size of the files phase, for the progress shown while it runs: the size of the
+	 * previous snapshot, or for a first backup the users' files, versions and trash as Nextcloud's
+	 * file cache knows them (approximate: other data in the data directory is not counted).
+	 *
+	 * @return array{bytes: int, approximate: bool}
+	 */
+	private function estimateBytes(Run $run, array $files): array {
+		if (($files['parent'] ?? null) !== null) {
+			try {
+				return ['bytes' => $this->snapshots->findOne($run->getTargetId(), (string)$files['parent'])->getBytes() ?? 0, 'approximate' => false];
+			} catch (\Throwable) {
+			}
+		}
+		try {
+			$qb = $this->db->getQueryBuilder();
+			$qb->select('numeric_id')->from('storages')
+				->where($qb->expr()->like('id', $qb->createNamedParameter('home::%')))
+				->orWhere($qb->expr()->like('id', $qb->createNamedParameter('object::user:%')));
+			$result = $qb->executeQuery();
+			$storages = [];
+			while (($id = $result->fetchOne()) !== false) {
+				$storages[] = (int)$id;
+			}
+			$result->closeCursor();
+			$bytes = 0;
+			foreach (array_chunk($storages, 500) as $chunk) {
+				$qb = $this->db->getQueryBuilder();
+				$qb->select($qb->func()->sum('size'))->from('filecache')
+					->where($qb->expr()->in('storage', $qb->createNamedParameter($chunk, IQueryBuilder::PARAM_INT_ARRAY)))
+					->andWhere($qb->expr()->in('path_hash', $qb->createNamedParameter(array_map('md5', ['files', 'files_versions', 'files_trashbin']), IQueryBuilder::PARAM_STR_ARRAY)))
+					->andWhere($qb->expr()->gt('size', $qb->createNamedParameter(0, IQueryBuilder::PARAM_INT)));
+				$bytes += (int)$qb->executeQuery()->fetchOne();
+			}
+			return ['bytes' => $bytes, 'approximate' => true];
+		} catch (\Throwable) {
+			return ['bytes' => 0, 'approximate' => true];
+		}
+	}
+
 	private function createRun(Target $target, string $label): Run {
 		$running = $this->runs->findRunning($target->getId(), self::KIND_FULL);
 		if ($running !== []) {
@@ -101,10 +157,22 @@ final class BackupService {
 	/**
 	 * Do one step of a run until $deadline. Safe to call concurrently: a second caller finds the
 	 * run locked and returns immediately.
+	 *
+	 * @param Repository|null $repo the location's repository, opened by an earlier step of this run
+	 *                              in this process (see runToCompletion()); set when this step opens it
 	 */
-	public function step(Run $run, float $deadline): Run {
+	public function step(Run $run, float $deadline, ?Repository &$repo = null): Run {
 		// Leases expire on their own: a step killed by a time limit or OOM blocks nothing for long.
-		$ttl = (int)min(3600, max(120, $deadline - microtime(true) + 120));
+		// A step can run well past its deadline (the commit of a large snapshot writes its tree and
+		// index), so the lease holds at least 15 minutes; should it still expire and another process
+		// take the run over, the checks below keep the two from overwriting each other.
+		$ttl = (int)min(3600, max(900, $deadline - microtime(true) + 600));
+		// No new step once a cancel has begun: it waits for the step in progress, if any.
+		try {
+			$this->leases->release($this->leases->acquire(self::cancelKey($run->getId()), LeaseService::SHARED, 60));
+		} catch (LockedException) {
+			return $run;
+		}
 		try {
 			$runLease = $this->leases->acquire('run/' . $run->getId(), LeaseService::EXCLUSIVE, $ttl);
 		} catch (LockedException) {
@@ -117,13 +185,28 @@ final class BackupService {
 			$this->leases->release($runLease);
 			return $run;
 		}
+		$loadedAt = null;
+		$savedBefore = $run->getUpdatedAt();
 		try {
 			$run = $this->runs->find($run->getId()); // fresh state after acquiring the lock
 			if ($run->getStatus() !== Run::RUNNING || $run->getKind() !== self::KIND_FULL) {
 				return $run;
 			}
+			$loadedAt = $run->getUpdatedAt();
 			$target = $this->targets->get((string)$run->getTargetId());
-			$repo = $this->targets->repository($target);
+			// Reopen when another process took a step since ours (its packs are not in our copy of
+			// the index) or the location was edited (password, folder, size limit).
+			$settings = json_encode([$target->getBackend(), $target->getAuth(), $target->getOptions(),
+				$target->getBasePath(), $target->getRepositoryId(), $target->getMaxBytes()], JSON_THROW_ON_ERROR);
+			if ($repo === null || $loadedAt !== $savedBefore || ($this->openedWith[$repo] ?? null) !== $settings) {
+				// Opening reads the index listing, which takes minutes on a slow location with many
+				// packs: that time does not count, or each step would store one blob and stop.
+				$opening = microtime(true);
+				$repo = null;
+				$repo = $this->targets->repository($target);
+				$this->openedWith[$repo] = $settings;
+				$deadline += microtime(true) - $opening;
+			}
 			$state = json_decode($run->getState(), true, 512, JSON_THROW_ON_ERROR);
 
 			if ($run->getPhase() === 'db') {
@@ -146,10 +229,40 @@ final class BackupService {
 					$state['dump'] = $dump;
 				}
 			} else {
+				$state['files']['estimate'] ??= $this->estimateBytes($run, $state['files']);
 				$state['files'] = BackupRun::step($repo, $state['files'], $deadline);
+				if (in_array($state['files']['phase'], ['finish', 'commit'], true)) {
+					$run->setPhase('commit'); // all files read: writing and recording the snapshot
+				}
+				if ($state['files']['phase'] === 'commit') {
+					// Catalog write under the catalog lock, from a repository opened inside it: a per-user
+					// export or restore may have written the catalog since this step opened $repo.
+					try {
+						$this->leases->with(PruneService::catalogLockKey($target), LeaseService::EXCLUSIVE, 300,
+							fn () => $this->targets->repository($target)->recordSnapshot((string)$state['files']['snapshot']));
+						$state['files']['phase'] = 'done';
+					} catch (LockedException|RepositoryException) {
+						// Another catalog write is in progress (or just raced us to the next
+						// generation): the next step retries this commit on the fresh catalog.
+					}
+				}
 				if ($state['files']['phase'] === 'done') {
 					$this->recordSnapshot($run, $state['files']);
-					$this->alerts->storedBytes($target, $repo->storedBytes());
+					// The snapshot is committed: what follows only reports on it and must not turn
+					// the run into a failure.
+					try {
+						$this->alerts->storedBytes($target, $repo->storedBytes());
+						$stats = $state['files']['stats'];
+						if (($stats['unreadable'] ?? 0) > 0 || ($stats['changing'] ?? 0) > 0) {
+							$warnings = BackupRun::warnings($state['files']);
+							$this->logger->warning(sprintf('NG Backup run %d to %s: %d unreadable (missing from the snapshot): %s; %d changed while being read: %s',
+								$run->getId(), $target->getName(), $stats['unreadable'] ?? 0, implode(', ', $warnings['unreadable']),
+								$stats['changing'] ?? 0, implode(', ', $warnings['changing'])));
+							$this->alerts->runWarnings($run, $target->getName(), (int)($stats['unreadable'] ?? 0), (int)($stats['changing'] ?? 0), $warnings);
+						}
+					} catch (\Throwable $e) {
+						$this->logger->warning('NG Backup run ' . $run->getId() . ': reporting on the finished backup failed: ' . $e->getMessage(), ['exception' => $e]);
+					}
 					$run->setStatus(Run::DONE);
 					$run->setPhase('done');
 					$run->setFinishedAt(time());
@@ -157,15 +270,33 @@ final class BackupService {
 			}
 			$run->setState(json_encode($state, JSON_THROW_ON_ERROR));
 			$run->setStats(json_encode(['db' => $state['dbStats'] ?? null, 'files' => $state['files']['stats']], JSON_THROW_ON_ERROR));
-			$run->setUpdatedAt(time());
-			return $this->runs->update($run);
+			// Another process may have taken the run over after this step's lease expired: then its
+			// writes stand and this step's are dropped.
+			$saved = $this->runs->updateIfUnchanged($run, $loadedAt);
+			if ($saved === null) {
+				$repo = null; // the run is another process's now: its packs are not in our index
+				return $this->runs->find($run->getId());
+			}
+			return $saved;
 		} catch (\Throwable $e) {
-			$this->logger->error('NG Backup run ' . $run->getId() . ' failed: ' . $e->getMessage(), ['exception' => $e]);
+			$repo = null; // may hold blobs of a half-written pack: the next step opens it afresh
+			if ($loadedAt === null) {
+				// The run could not even be loaded: there is nothing fresh to mark as failed, and
+				// the caller's copy may be stale.
+				$this->logger->error('NG Backup run ' . $run->getId() . ': step could not load the run: ' . $e->getMessage(), ['exception' => $e]);
+				return $run;
+			}
 			$run->setStatus(Run::FAILED);
 			$run->setError($e->getMessage());
 			$run->setFinishedAt(time());
-			$run->setUpdatedAt(time());
-			$run = $this->runs->update($run);
+			$failed = $this->runs->updateIfUnchanged($run, $loadedAt);
+			if ($failed === null) {
+				// Another process that took the run over may have finished it: its result stands.
+				$this->logger->warning('NG Backup run ' . $run->getId() . ': a step that another process had taken over ended with: ' . $e->getMessage());
+				return $this->runs->find($run->getId());
+			}
+			$run = $failed;
+			$this->logger->error('NG Backup run ' . $run->getId() . ' failed: ' . $e->getMessage(), ['exception' => $e]);
 			try {
 				$this->alerts->runFailed($run, isset($target) ? $target->getName() : '#' . $run->getTargetId());
 			} catch (\Throwable) {
@@ -179,14 +310,16 @@ final class BackupService {
 
 	/** Run to completion in this process (occ, system cron), reporting progress. */
 	public function runToCompletion(Run $run, ?callable $progress = null, float $stepSeconds = 30): Run {
+		$repo = null; // opened once, by the first step, and kept for the next ones
 		while ($run->getStatus() === Run::RUNNING) {
 			$before = $run->getUpdatedAt();
-			$run = $this->step($run, microtime(true) + $stepSeconds);
+			$run = $this->step($run, microtime(true) + $stepSeconds, $repo);
 			if ($run->getStatus() === Run::RUNNING && $run->getUpdatedAt() === $before) {
 				// Step was not possible (another process holds the run, or a crashed step's lease has
 				// not expired yet): wait instead of spinning.
 				sleep(5);
 				$run = $this->runs->find($run->getId());
+				$repo = null; // another process may have stored packs in the meantime
 			}
 			if ($progress !== null) {
 				$progress($run);
@@ -195,14 +328,78 @@ final class BackupService {
 		return $run;
 	}
 
-	public function cancel(Run $run): Run {
-		$run->setStatus(Run::CANCELLED);
-		$run->setFinishedAt(time());
-		$run->setUpdatedAt(time());
-		return $this->runs->update($run);
+	/**
+	 * Stop a running backup. First no new step may start, then this waits (up to $wait seconds)
+	 * for the step in progress, so a step that is recording the snapshot finishes first. A process
+	 * running the backup then finds it cancelled and stops. The packs it stored stay until the
+	 * next cleanup.
+	 *
+	 * A process of an earlier version does not hold back its next step and may never leave a gap:
+	 * after $wait the run is marked cancelled while it works, unless it is recording the snapshot.
+	 * Its step then fails to save and the process stops.
+	 */
+	public function cancel(Run $run, int $wait = 120): Run {
+		$id = $run->getId();
+		$until = time() + $wait;
+		$hold = null;
+		for ($try = 0; $hold === null; $try++) {
+			try {
+				$hold = $this->leases->acquire(self::cancelKey($id), LeaseService::EXCLUSIVE, $wait + 300);
+			} catch (LockedException) {
+				if ($try >= 20) {
+					throw new \RuntimeException("Run $id is being cancelled already");
+				}
+				usleep(100000); // a step checking whether it may start
+			}
+		}
+		try {
+			$lease = null;
+			while ($lease === null && time() < $until) {
+				try {
+					$lease = $this->leases->acquire('run/' . $id, LeaseService::EXCLUSIVE, 60);
+				} catch (LockedException) {
+					sleep(2);
+				}
+			}
+			try {
+				for ($try = 0; $try < 10; $try++) {
+					$run = $this->runs->find($id);
+					if ($run->getStatus() !== Run::RUNNING) {
+						return $run;
+					}
+					$state = json_decode($run->getState(), true) ?: [];
+					if ($lease === null && ($state['files']['phase'] ?? '') === 'commit') {
+						throw new \RuntimeException("Run $id is recording its snapshot; try again in a minute");
+					}
+					$loadedAt = $run->getUpdatedAt();
+					$run->setStatus(Run::CANCELLED);
+					$run->setFinishedAt(time());
+					if (($cancelled = $this->runs->updateIfUnchanged($run, $loadedAt)) !== null) {
+						return $cancelled;
+					}
+					usleep(200000); // a step of another process saved just now
+				}
+				throw new \RuntimeException("Run $id keeps changing; try again");
+			} finally {
+				if ($lease !== null) {
+					$this->leases->release($lease);
+				}
+			}
+		} finally {
+			$this->leases->release($hold);
+		}
+	}
+
+	private static function cancelKey(int $runId): string {
+		return 'run/' . $runId . '/cancel';
 	}
 
 	private function recordSnapshot(Run $run, array $files): void {
+		try {
+			$this->snapshots->findOne($run->getTargetId(), $files['snapshot']);
+			return; // already recorded, by an earlier attempt at this step
+		} catch (DoesNotExistException) {
+		}
 		$s = new Snapshot();
 		$s->setTargetId($run->getTargetId());
 		$s->setSnapshotId($files['snapshot']);
@@ -211,7 +408,19 @@ final class BackupService {
 		$s->setCreatedAt(time());
 		$s->setFiles($files['stats']['files']);
 		$s->setBytes($files['stats']['bytes']);
-		$this->snapshots->insert($s);
+		try {
+			$this->snapshots->insert($s);
+		} catch (\OCP\DB\Exception $e) {
+			// Recorded by another process between the check above and this insert?
+			if ($e->getReason() !== \OCP\DB\Exception::REASON_UNIQUE_CONSTRAINT_VIOLATION) {
+				throw $e;
+			}
+			try {
+				$this->snapshots->findOne($run->getTargetId(), $files['snapshot']);
+			} catch (DoesNotExistException) {
+				throw $e;
+			}
+		}
 	}
 
 	/** @return list<string> */

lib/Service/CronHealth.php

@@ -0,0 +1,97 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\Service;
+
+use OCA\NgBackup\Db\Run;
+use OCP\Exceptions\AppConfigTypeConflictException;
+use OCP\IAppConfig;
+use OCP\IURLGenerator;
+
+/**
+ * Whether Nextcloud's background jobs run on a system cron, which backups need: a backup moves
+ * forward only when a background job run takes its next step (#13). Without system cron, AJAX
+ * cron runs a job only now and then while someone has Nextcloud open, and webcron only as often as
+ * the outside service calls it.
+ */
+final class CronHealth {
+	/** A system cron that has not run for this long has stopped (it runs every 5 minutes). */
+	public const STOPPED_AFTER = 3600;
+
+	/**
+	 * A running backup that took no step for this long is waiting for background jobs. A step with
+	 * system cron takes at most a few minutes (BackupJob) and the job runs every minute.
+	 */
+	public const WAITING_AFTER = 900;
+
+	public function __construct(
+		private IAppConfig $appConfig,
+		private IURLGenerator $urls,
+	) {
+	}
+
+	/**
+	 * mode: ajax, webcron or cron; lastRun: the last background job run (0: never); ok: a system
+	 * cron that ran recently; stopped: system cron is set but has not run for STOPPED_AFTER.
+	 *
+	 * @return array{mode: string, lastRun: int, ok: bool, stopped: bool, docs: string}
+	 */
+	public function check(?int $now = null): array {
+		$now ??= time();
+		$mode = $this->coreString('backgroundjobs_mode', 'ajax');
+		$lastRun = (int)$this->coreString('lastcron', '0');
+		$stopped = $mode === 'cron' && $now - $lastRun > self::STOPPED_AFTER;
+		return [
+			'mode' => $mode,
+			'lastRun' => $lastRun,
+			'ok' => $mode === 'cron' && !$stopped,
+			'stopped' => $stopped,
+			'docs' => $this->urls->linkToDocs('admin-background-jobs'),
+		];
+	}
+
+	/**
+	 * Seconds since a running backup took its last step, when that is long enough to say it waits
+	 * for background jobs; null while it moves (or when it is not running).
+	 */
+	public static function waitingFor(Run $run, ?int $now = null): ?int {
+		$idle = ($now ?? time()) - $run->getUpdatedAt();
+		return $run->getStatus() === Run::RUNNING && $idle >= self::WAITING_AFTER ? $idle : null;
+	}
+
+	/** One line for occ and the log; null when system cron runs. */
+	public static function describe(array $health, ?int $now = null): ?string {
+		if ($health['ok']) {
+			return null;
+		}
+		$last = $health['lastRun'] > 0 ? 'last ran ' . self::ago(($now ?? time()) - $health['lastRun']) : 'never ran';
+		$what = $health['stopped']
+			? 'Background jobs are set to system cron, but cron has not run for over an hour (' . $last . ').'
+			: 'Background jobs do not run on a system cron: they are set to "' . ($health['mode'] === 'webcron' ? 'Webcron' : 'AJAX') . '" and ' . $last . '.';
+		return $what . ' Backups, also the scheduled ones, need a system cron that runs every 5 minutes: ' . $health['docs'];
+	}
+
+	/** "12 min ago" style, for durations from a minute to days */
+	public static function ago(int $seconds): string {
+		if ($seconds < 3600) {
+			return max(1, intdiv($seconds, 60)) . ' min ago';
+		}
+		if ($seconds < 172800) {
+			return intdiv($seconds, 3600) . ' h ago';
+		}
+		return intdiv($seconds, 86400) . ' days ago';
+	}
+
+	/** Core stores these with different value types across versions: read whatever is there. */
+	private function coreString(string $key, string $default): string {
+		try {
+			return $this->appConfig->getValueString('core', $key, $default);
+		} catch (AppConfigTypeConflictException) {
+			return (string)$this->appConfig->getValueInt('core', $key, (int)$default);
+		}
+	}
+}

lib/Service/KeyService.php

@@ -31,6 +31,11 @@ final class KeyService {
 	private const KEY_KIT_VERSION = 'recovery_kit_version';
 	private const KEY_KIT_CODE = 'recovery_kit_code';
 	public const DEFAULT_DELETE_DELAY = 7;
+	/**
+	 * The location holds the passphrase-wrapped key too, so whoever can read it can try
+	 * passphrases offline: the passphrase is what really protects the backups.
+	 */
+	public const MIN_PASSPHRASE = 16;
 
 	private ?KeyRing $cached = null;
 
@@ -56,9 +61,7 @@ final class KeyService {
 		if ($this->isInitialized()) {
 			throw new \RuntimeException('A backup key already exists');
 		}
-		if (strlen($passphrase) < 12) {
-			throw new \InvalidArgumentException('The passphrase must be at least 12 characters');
-		}
+		self::checkPassphrase($passphrase);
 		$keys = KeyRing::generate();
 		$this->appConfig->setValueString(Application::APP_ID, self::KEY_MASTER,
 			$this->crypto->encrypt(base64_encode($keys->exportMasterKey())), true, true);
@@ -71,6 +74,86 @@ final class KeyService {
 		$this->cached = $keys;
 	}
 
+	/**
+	 * Disaster recovery on a fresh installation: adopt the master key from a recovery kit
+	 * (occ backup:key:kit on the original installation) instead of generating a new one.
+	 * Afterwards occ backup:target:add opens the existing repository on the location with this
+	 * key, instead of creating a new, empty one.
+	 *
+	 * @param array<string, mixed> $kit as produced by recoveryKit()
+	 * @throws \OCA\NgBackup\Crypto\CryptoException wrong passphrase, or a damaged/foreign kit
+	 */
+	public function importRecoveryKit(array $kit, #[\SensitiveParameter] string $passphrase): void {
+		if ($this->isInitialized()) {
+			throw new \RuntimeException('A backup key already exists');
+		}
+		if (!isset($kit['wrapped_key'])) {
+			throw new \InvalidArgumentException('Not a NG Backup recovery kit file');
+		}
+		$keys = KeyRing::unwrapAny($kit['wrapped_key'], $passphrase);
+		$this->appConfig->setValueString(Application::APP_ID, self::KEY_MASTER,
+			$this->crypto->encrypt(base64_encode($keys->exportMasterKey())), true, true);
+		$this->cached = $keys;
+		$this->appConfig->setValueString(Application::APP_ID, self::KEY_WRAPPED, json_encode($kit['wrapped_key'], JSON_THROW_ON_ERROR), true, true);
+		$this->appConfig->setValueString(Application::APP_ID, self::KEY_FINGERPRINT, $this->fingerprintOf($keys), true);
+		// Kits from before this field existed fall back to the default.
+		$delay = (int)($kit['delete_delay_days'] ?? self::DEFAULT_DELETE_DELAY);
+		$this->appConfig->setValueInt(Application::APP_ID, self::KEY_DELETE_DELAY, ($delay >= 1 && $delay <= 365) ? $delay : self::DEFAULT_DELETE_DELAY, true);
+		$this->appConfig->setValueInt(Application::APP_ID, self::KEY_KIT_VERSION, (int)($kit['kit_version'] ?? 1), true);
+		// Having and successfully using a real kit file is stronger proof than the normal
+		// download-and-confirm flow it replaces.
+		$this->confirmRecoveryKit('cli-import');
+	}
+
+	/**
+	 * The master key and the recovery kit code are stored encrypted with Nextcloud's own
+	 * instance secret (ICrypto), not with themselves; the wrapped key is not (it is sealed with
+	 * the admin's passphrase instead), but Nextcloud's own AppConfig additionally encrypts any
+	 * "sensitive" value with the instance secret regardless, underneath whatever we store. So
+	 * changing that secret (occ backup:restore:full merging config.php) would otherwise leave
+	 * all three permanently undecryptable. Call $applySecretChange (which must be the only thing
+	 * that changes the secret) through here instead: all three are decrypted first, then
+	 * re-encrypted under whatever secret is active once $applySecretChange returns.
+	 *
+	 * Not crash-safe: a process kill between the delete and the re-save of one of these keys
+	 * would leave it missing rather than merely stale. Disaster recovery is run once, by hand,
+	 * right after occ maintenance:install; a dedicated two-phase write is not justified yet for
+	 * that narrow a window.
+	 */
+	public function reencryptForSecretRotation(callable $applySecretChange): mixed {
+		$master = $this->appConfig->getValueString(Application::APP_ID, self::KEY_MASTER, '', true);
+		$wrapped = $this->appConfig->getValueString(Application::APP_ID, self::KEY_WRAPPED, '', true);
+		$kitCodeRaw = $this->appConfig->getValueString(Application::APP_ID, self::KEY_KIT_CODE, '', true);
+		$kitCode = $kitCodeRaw !== '' ? json_decode($kitCodeRaw, true, 512, JSON_THROW_ON_ERROR) : null;
+		$masterPlain = $master !== '' ? $this->crypto->decrypt($master) : null;
+		$kitCodePlain = $kitCode !== null && isset($kitCode['code']) ? $this->crypto->decrypt($kitCode['code']) : null;
+
+		$result = $applySecretChange();
+		$this->cached = null; // the master key is about to be re-saved; do not keep the pre-rotation copy
+
+		// Nextcloud's own AppConfig additionally encrypts a "sensitive" value itself (tied to
+		// the same secret, underneath our own encrypt() above); setValueString() on an existing
+		// key reads the old value first to compare, which would try to decrypt it with the new
+		// secret and fail the same way. Delete first so there is nothing to compare against.
+		if ($masterPlain !== null) {
+			$this->appConfig->deleteKey(Application::APP_ID, self::KEY_MASTER);
+			$this->appConfig->setValueString(Application::APP_ID, self::KEY_MASTER, $this->crypto->encrypt($masterPlain), true, true);
+		}
+		if ($wrapped !== '') {
+			// Already plaintext JSON here: getValueString() above transparently undid
+			// AppConfig's own sensitive-value encryption; there is no encrypt() of our own to
+			// redo (wrapping is sealed with the passphrase, not the instance secret).
+			$this->appConfig->deleteKey(Application::APP_ID, self::KEY_WRAPPED);
+			$this->appConfig->setValueString(Application::APP_ID, self::KEY_WRAPPED, $wrapped, true, true);
+		}
+		if ($kitCodePlain !== null) {
+			$kitCode['code'] = $this->crypto->encrypt($kitCodePlain);
+			$this->appConfig->deleteKey(Application::APP_ID, self::KEY_KIT_CODE);
+			$this->appConfig->setValueString(Application::APP_ID, self::KEY_KIT_CODE, json_encode($kitCode, JSON_THROW_ON_ERROR), true, true);
+		}
+		return $result;
+	}
+
 	public function keyRing(): KeyRing {
 		if ($this->cached === null) {
 			$enc = $this->appConfig->getValueString(Application::APP_ID, self::KEY_MASTER, '', true);
@@ -154,8 +237,8 @@ final class KeyService {
 	}
 
 	private static function checkPassphrase(string $passphrase): void {
-		if (strlen($passphrase) < 12) {
-			throw new \InvalidArgumentException('The passphrase must be at least 12 characters');
+		if (strlen($passphrase) < self::MIN_PASSPHRASE) {
+			throw new \InvalidArgumentException('The passphrase must be at least ' . self::MIN_PASSPHRASE . ' characters');
 		}
 	}
 
@@ -182,13 +265,14 @@ final class KeyService {
 		return $this->appConfig->getValueString(Application::APP_ID, self::KEY_FINGERPRINT, '', true);
 	}
 
-	/** @return array{version:int, app:string, fingerprint:string, created:string, wrapped_key:array, instructions:string} */
+	/** @return array{version:int, app:string, fingerprint:string, kit_version:int, delete_delay_days:int, confirmation_code:string, created:string, wrapped_key:array, slots:list<array{slot:int, label:string, created:int}>, instructions:string} */
 	public function recoveryKit(): array {
 		return [
 			'version' => 1,
 			'app' => 'NG Backup',
 			'fingerprint' => $this->fingerprint(),
 			'kit_version' => $this->kitVersion(),
+			'delete_delay_days' => $this->deleteDelayDays(),
 			'confirmation_code' => $this->kitCode(),
 			'created' => gmdate('c'),
 			'wrapped_key' => $this->wrappedKey(),

lib/Service/LeaseService.php

@@ -76,6 +76,17 @@ final class LeaseService {
 		$qb->executeStatement();
 	}
 
+	/** Wraps $refresh so calling it often (per file, per row batch) only touches the database every $seconds. */
+	public static function throttled(callable $refresh, int $seconds = 60): \Closure {
+		$last = time();
+		return static function () use ($refresh, $seconds, &$last): void {
+			if (time() - $last >= $seconds) {
+				$refresh();
+				$last = time();
+			}
+		};
+	}
+
 	/** Run $fn under a lease; $refresh() can be called during long work. */
 	public function with(string $name, string $mode, int $ttl, callable $fn): mixed {
 		$id = $this->acquire($name, $mode, $ttl);

lib/Service/PruneService.php

@@ -98,6 +98,83 @@ final class PruneService {
 		return 'ng_backup/target/' . $target->getId();
 	}
 
+	/**
+	 * A separate, short-lived exclusive lock serializing writes to the catalog itself. The
+	 * per-target lock above only keeps readers/writers out while a cleanup runs; it does not
+	 * stop two SHARED holders (e.g. two concurrent per-user backups, or one alongside a full
+	 * backup) from both reading the same catalog generation and racing to write the next one,
+	 * silently dropping whichever's change loses. The full-backup path avoids this today only
+	 * because a Run row makes concurrent runs for the same target mutually exclusive; per-user
+	 * backup/restore has no such row, so it takes this lock around the catalog write itself.
+	 */
+	public static function catalogLockKey(Target $target): string {
+		return self::lockKey($target) . '/catalog';
+	}
+
+	/** How many of each user's own exports (occ backup:user:backup) to keep, newest first. */
+	public function userExportRetention(): int {
+		return $this->appConfig->getValueInt(Application::APP_ID, 'user_export_retention', 3);
+	}
+
+	public function setUserExportRetention(int $keep): void {
+		if ($keep < 1) {
+			throw new \InvalidArgumentException('Keep at least the last export');
+		}
+		$old = $this->userExportRetention();
+		$this->appConfig->setValueInt(Application::APP_ID, 'user_export_retention', $keep);
+		if ($old !== $keep) {
+			$this->alerts->securityEvent('user_export_retention_changed', ['keep' => (string)$keep]);
+		}
+	}
+
+	/**
+	 * Forgets a user's older exports once more than userExportRetention() exist for them,
+	 * newest first; no trash, unlike a full snapshot (occ backup:user:backup is on-demand, not
+	 * yet the primary safety net the deletion delay protects).
+	 *
+	 * @return array{kept: array<string, list<string>>, forgotten: list<string>}
+	 */
+	public function applyUserExports(Target $target, bool $dryRun = false): array {
+		if ($target->getAppendOnly()) {
+			throw new \RuntimeException('Location ' . $target->getName() . ' is append-only: NG Backup does not delete anything there');
+		}
+		$lease = $this->lockExclusive($target, 1800);
+		try {
+			$repo = $this->targets->repository($target);
+			$keep = $this->userExportRetention();
+			$byUser = [];
+			foreach ($repo->listUserExports() as $path) {
+				$uid = explode('/', $path)[1] ?? '';
+				$manifest = json_decode($repo->getObject($path), true, 512, JSON_THROW_ON_ERROR);
+				$byUser[$uid][$path] = (int)strtotime((string)($manifest['time'] ?? '@0'));
+			}
+			$kept = [];
+			$forget = [];
+			foreach ($byUser as $uid => $times) {
+				arsort($times);
+				$i = 0;
+				foreach (array_keys($times) as $path) {
+					if ($i++ < $keep) {
+						$kept[$uid][] = $path;
+					} else {
+						$forget[] = $path;
+					}
+				}
+			}
+			if (!$dryRun) {
+				foreach ($forget as $path) {
+					$repo->forgetUserExport($path);
+				}
+				if ($forget !== []) {
+					$this->alerts->securityEvent('user_exports_forgotten', ['target' => $target->getName(), 'count' => (string)count($forget)], false);
+				}
+			}
+			return ['kept' => $kept, 'forgotten' => $forget];
+		} finally {
+			$this->leases->release($lease);
+		}
+	}
+
 	public function policy(): RetentionPolicy {
 		return RetentionPolicy::fromArray(json_decode($this->appConfig->getValueString(Application::APP_ID, 'retention', '{}'), true) ?: []);
 	}

lib/Service/RestoreFullService.php

@@ -0,0 +1,373 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\Service;
+
+use OCA\NgBackup\Db\DbDumper;
+use OCA\NgBackup\Db\Target;
+use OCP\App\IAppManager;
+use OCP\IConfig;
+use OCP\IDBConnection;
+use OCP\Lock\LockedException;
+
+/**
+ * Disaster recovery on a fresh Nextcloud installation (same major version): replace the
+ * database, restore the data directory and merge the backed-up config.php, see PLAN.md 3.7.
+ *
+ * Deliberately NOT handled yet (phase 3): restoring in place over a live, already-used
+ * installation. The admin is expected to run this once, right after occ maintenance:install and
+ * occ backup:key:import/backup:target:add, before anyone else touches the instance.
+ */
+final class RestoreFullService {
+	/**
+	 * Config keys that must keep pointing at THIS installation's actual, already-working
+	 * database and data directory (set by occ maintenance:install), never at the old server's.
+	 */
+	/** App setting: when a full restore started that has not completed (see restoreFull()). */
+	private const INTERRUPTED_KEY = 'restore_full_started';
+
+	private const CONNECTION_KEYS = [
+		'dbtype', 'dbhost', 'dbport', 'dbname', 'dbuser', 'dbpassword', 'dbpersistent',
+		'dbtableprefix', 'dbdriveroptions', 'datadirectory',
+		// set by restoreFull() itself for the length of the restore
+		'maintenance',
+	];
+
+	public function __construct(
+		private TargetService $targets,
+		private RestoreService $restore,
+		private LeaseService $leases,
+		private IConfig $config,
+		private IDBConnection $db,
+		private IAppManager $appManager,
+		private KeyService $keys,
+	) {
+	}
+
+	/** Apps that only exist in a particular setup and are never needed elsewhere. */
+	private const ENVIRONMENT_APPS = ['nextcloud-aio'];
+
+	/**
+	 * Whether this installation can receive $snapshotId, all problems at once:
+	 * - the same Nextcloud major version is required;
+	 * - apps that were enabled at backup time but are not here (they work again once installed);
+	 * - tables in the backup that do not exist here: a backup made from 1.0.0-rc.2 on records
+	 *   their structure and the restore creates them, an older one cannot (missingTables).
+	 *
+	 * With $salvage, a database dump that cannot be read does not block: dbUnreadable says why, and
+	 * the restore then salvages the files instead (see restoreFull()).
+	 *
+	 * @return array{ok:bool, currentMajor:string, snapshotMajor:string, missingApps:list<string>, missingTables:list<string>, dbUnreadable?:string}
+	 */
+	public function checkCompatibility(Target $target, string $snapshotId, bool $skipMissingTables = false, bool $salvage = false): array {
+		$repo = $this->targets->repository($target);
+		$meta = $repo->snapshotMeta($snapshotId);
+		$currentMajor = explode('.', $this->config->getSystemValueString('version'))[0];
+		$snapshotMajor = explode('.', (string)($meta['nextcloud'] ?? ''))[0];
+		$enabled = array_flip($this->appManager->getEnabledApps());
+		$missingApps = array_values(array_diff(array_keys($meta['apps'] ?? []), array_keys($enabled), self::ENVIRONMENT_APPS));
+		$missingTables = [];
+		$prefixMismatch = null;
+		$dbUnreadable = null;
+		$manifest = null;
+		if (isset($meta['db'])) {
+			try {
+				$manifest = json_decode($repo->getObject($meta['db']), true, 512, JSON_THROW_ON_ERROR);
+			} catch (\Throwable $e) {
+				if (!$salvage) {
+					throw $e;
+				}
+				$dbUnreadable = 'the database dump cannot be read: ' . $e->getMessage();
+			}
+		}
+		if (is_array($manifest)) {
+			$prefix = $this->config->getSystemValueString('dbtableprefix', 'oc_');
+			$sourcePrefix = DbDumper::dumpPrefix($manifest);
+			if ($sourcePrefix !== null && $sourcePrefix !== $prefix) {
+				$prefixMismatch = [$sourcePrefix, $prefix];
+			}
+			$dumper = new DbDumper($this->db->getInner(), $prefix);
+			$missingTables = array_values(array_filter($dumper->missingTables($manifest),
+				fn (string $t) => !isset($manifest['tables'][$t]['schema']) && !str_starts_with($t, $prefix . 'ngb_')));
+		}
+		return [
+			'ok' => $currentMajor === $snapshotMajor && $prefixMismatch === null && ($missingTables === [] || $skipMissingTables),
+			'currentMajor' => $currentMajor,
+			'snapshotMajor' => $snapshotMajor,
+			'missingApps' => $missingApps,
+			'missingTables' => $prefixMismatch === null ? $missingTables : [],
+			'prefixMismatch' => $prefixMismatch,
+		] + ($dbUnreadable !== null ? ['dbUnreadable' => $dbUnreadable] : []);
+	}
+
+	/**
+	 * With $salvage, restore whatever can be restored instead of stopping:
+	 * - a file that cannot be read or decrypted is left out and listed (skipped);
+	 * - when the database cannot be restored here (its dump is unreadable or damaged, or it does
+	 *   not fit this installation), the fresh database stays as it is, and the data directory and
+	 *   config of the backup go to a folder of their own (salvageDir) instead: the files are what
+	 *   matters most, and putting Nextcloud back together from there is work by hand;
+	 * - a config.php that cannot be read is not merged (configError).
+	 *
+	 * @return array{dbReport:array, dataFiles:int, configKeys:int, dbConsistent:bool, missingApps:list<string>, maintenanceLeftOn:bool, skipped:array<string, string>, dbError:?string, salvageDir:?string, configError:?string}
+	 */
+	public function restoreFull(Target $target, string $snapshotId, bool $skipMissingTables = false, bool $salvage = false): array {
+		// Maintenance mode for the whole restore: background jobs (cron.php stops in maintenance
+		// mode), page visits (AJAX cron) and users must not write into tables or the data
+		// directory while they are being replaced; a row written in between would collide with a
+		// restored one or be silently lost. Switched off after a restore that completed. After an
+		// error it stays on: the instance may be partly restored, and must not be used like that.
+		// occ only offers app commands outside maintenance mode, so the admin switches it off
+		// right before running the restore again (see RestoreFull). Already on before: left on.
+		// On before the checks below, so that a run again after an error leaves the partly
+		// restored instance open for seconds at most; off again when they refuse (nothing changed).
+		// A marker in ng_backup's own app settings (which the restore keeps) says a restore started
+		// and did not complete: then the instance may be partly restored, and a check that refuses
+		// a run again must not open it.
+		$appConfig = \OCP\Server::get(\OCP\IAppConfig::class);
+		$interrupted = $appConfig->getValueInt(\OCA\NgBackup\AppInfo\Application::APP_ID, self::INTERRUPTED_KEY, 0) > 0;
+		$wasInMaintenance = $this->config->getSystemValueBool('maintenance', false);
+		$this->config->setSystemValue('maintenance', true);
+		$reopen = function () use ($wasInMaintenance, $interrupted): void {
+			if (!$wasInMaintenance && !$interrupted) {
+				$this->config->setSystemValue('maintenance', false);
+			}
+		};
+		try {
+			$check = $this->checkCompatibility($target, $snapshotId, $skipMissingTables, $salvage);
+		} catch (\Throwable $e) {
+			$reopen();
+			throw $e;
+		}
+		if (!$check['ok']) {
+			if (!$salvage) {
+				$reopen();
+				throw new \RuntimeException($this->describeBlockers($check));
+			}
+			// The database cannot go into this installation; the files can.
+			$check['dbUnreadable'] = 'the database cannot be restored here: ' . $this->describeBlockers($check);
+		}
+		$appConfig->setValueInt(\OCA\NgBackup\AppInfo\Application::APP_ID, self::INTERRUPTED_KEY, time());
+		$result = $this->restoreInMaintenance($target, $snapshotId, $skipMissingTables, $check, $salvage);
+		$appConfig->deleteKey(\OCA\NgBackup\AppInfo\Application::APP_ID, self::INTERRUPTED_KEY);
+		if (!$wasInMaintenance) {
+			$this->config->setSystemValue('maintenance', false);
+		}
+		return $result + ['maintenanceLeftOn' => $wasInMaintenance];
+	}
+
+	/** @return array{dbReport:array, dataFiles:int, configKeys:int, dbConsistent:bool, missingApps:list<string>, skipped:array<string, string>, dbError:?string, salvageDir:?string, configError:?string} */
+	private function restoreInMaintenance(Target $target, string $snapshotId, bool $skipMissingTables, array $check, bool $salvage): array {
+		return $this->withSharedLock($target, function (callable $refresh) use ($target, $snapshotId, $skipMissingTables, $check, $salvage) {
+			$beat = LeaseService::throttled($refresh);
+			$repo = $this->targets->repository($target);
+			$meta = $repo->snapshotMeta($snapshotId);
+
+			$dbReport = null;
+			$manifest = [];
+			$dbError = $check['dbUnreadable'] ?? null;
+			$skipped = $salvage ? [] : null;
+			$dataDir = rtrim($this->config->getSystemValueString('datadirectory'), '/');
+			if ($dbError === null) {
+				try {
+					$this->restoreDatabase($repo, $meta, $manifest, $dbReport, $beat, $skipMissingTables);
+				} catch (\Throwable $e) {
+					if (!$salvage) {
+						throw $e;
+					}
+					// DbDumper::restore() rolled its transaction back: the database is the fresh one.
+					$dbError = 'the database could not be restored: ' . $e->getMessage();
+					$dbReport = null;
+				}
+			}
+			if ($dbError !== null) {
+				$salvageDir = $dataDir . '/ngb-salvage-' . substr($snapshotId, 0, 12);
+				$dataFiles = $this->restore->restoreToDirectory($target, $snapshotId, 'data', $salvageDir . '/data', stripPrefix: true, heartbeat: $beat, skipped: $skipped, keepUnchanged: true);
+				$this->restore->restoreToDirectory($target, $snapshotId, 'config', $salvageDir . '/config', stripPrefix: true, heartbeat: $beat, skipped: $skipped);
+				return ['dbReport' => ['skipped' => [], 'restored' => [], 'created' => [], 'missing' => []], 'dataFiles' => $dataFiles, 'configKeys' => 0,
+					'dbConsistent' => true, 'missingApps' => $check['missingApps'], 'skipped' => $skipped ?? [], 'dbError' => $dbError,
+					'salvageDir' => $salvageDir, 'configError' => null];
+			}
+
+			// Read (but do not yet apply) the backed-up config.php before touching the data
+			// directory: once applied, 'secret' may differ from what ng_backup's own Target
+			// options were encrypted with (see restoreFull()'s docblock), and every further
+			// repository access through $this->targets would fail to decrypt them.
+			$configError = null;
+			try {
+				/** @var array<string, mixed> $backupConfig */
+				$backupConfig = $this->fetchBackupConfig($target, $snapshotId, $salvage);
+			} catch (\Throwable $e) {
+				if (!$salvage) {
+					throw $e;
+				}
+				$configError = $e->getMessage();
+				$backupConfig = [];
+			}
+
+			$dataFiles = $this->restore->restoreToDirectory($target, $snapshotId, 'data', $dataDir, stripPrefix: true, heartbeat: $beat, skipped: $skipped, keepUnchanged: true);
+
+			// Last step: nothing after this may need $this->targets->repository($target) again.
+			if ($backupConfig !== []) {
+				$this->targets->reencryptOptionsAround(
+					fn (): mixed => $this->keys->reencryptForSecretRotation(fn (): mixed => $this->config->setSystemValues($backupConfig)),
+				);
+			}
+
+			return ['dbReport' => $dbReport ?? ['skipped' => [], 'restored' => [], 'created' => [], 'missing' => []], 'dataFiles' => $dataFiles, 'configKeys' => count($backupConfig),
+				'dbConsistent' => (bool)($manifest['consistent'] ?? true), 'missingApps' => $check['missingApps'],
+				'skipped' => $skipped ?? [], 'dbError' => null, 'salvageDir' => null, 'configError' => $configError];
+		});
+	}
+
+	/**
+	 * Replace the database with the snapshot's dump (one transaction, see DbDumper::restore()).
+	 *
+	 * @param array<string, mixed> $meta the snapshot's meta record
+	 * @param array $manifest set to the dump's manifest
+	 */
+	private function restoreDatabase(\OCA\NgBackup\Repository\Repository $repo, array $meta, array &$manifest, ?array &$dbReport, callable $beat, bool $skipMissingTables): void {
+		if (!isset($meta['db'])) {
+			return;
+		}
+		$manifest = json_decode($repo->getObject($meta['db']), true, 512, JSON_THROW_ON_ERROR);
+		$prefix = $this->config->getSystemValueString('dbtableprefix', 'oc_');
+		// ng_backup's own tables (and its own rows in the shared appconfig table) must
+		// survive this restore untouched: they describe the backup/key/target that is
+		// actively performing it right now, on THIS installation, not the one that was
+		// backed up. Overwriting them mid-restore would pull the rug from under it.
+		foreach (array_keys($manifest['tables']) as $table) {
+			/** @var string $table */
+			if (str_starts_with($table, $prefix . 'ngb_')) {
+				unset($manifest['tables'][$table]);
+			}
+		}
+		// Sequences are keyed separately from tables; excluding a table does not exclude
+		// its sequence, which would otherwise rewind a retained ngb_* table's sequence
+		// below its current ids (PostgreSQL only -- see DbDumper::restoreSequences()).
+		foreach (array_keys($manifest['sequences'] ?? []) as $seq) {
+			/** @var string $seq */
+			if (str_starts_with((string)($manifest['sequences'][$seq]['table'] ?? ''), $prefix . 'ngb_')) {
+				unset($manifest['sequences'][$seq]);
+			}
+		}
+		$ownAppConfig = $this->preserveOwnAppConfig();
+		$dumper = new DbDumper($this->db->getInner(), $prefix);
+		try {
+			$dumper->restore($repo, $manifest, $dbReport, $beat, $skipMissingTables);
+		} finally {
+			$this->restoreOwnAppConfig($ownAppConfig);
+		}
+	}
+
+	/**
+	 * @return array<string, mixed> config.php's $CONFIG from the backup, minus the connection keys
+	 * @throws \RuntimeException with $salvage, when config.php itself cannot be read
+	 */
+	private function fetchBackupConfig(Target $target, string $snapshotId, bool $salvage = false): array {
+		$tmp = sys_get_temp_dir() . '/ngb-restore-config-' . bin2hex(random_bytes(6));
+		try {
+			$skipped = $salvage ? [] : null;
+			$this->restore->restoreToDirectory($target, $snapshotId, 'config', $tmp, stripPrefix: true, skipped: $skipped);
+			if (isset($skipped['config/config.php'])) {
+				throw new \RuntimeException('config.php cannot be read: ' . $skipped['config/config.php']);
+			}
+			$path = $tmp . '/config.php';
+			if (!is_file($path)) {
+				return []; // nothing to merge; the live config.php stays as occ maintenance:install made it
+			}
+			$backupConfig = (static function () use ($path): array {
+				$CONFIG = [];
+				include $path;
+				return $CONFIG;
+			})();
+			foreach (self::CONNECTION_KEYS as $key) {
+				unset($backupConfig[$key]);
+			}
+			return $backupConfig;
+		} finally {
+			$this->rmrf($tmp);
+		}
+	}
+
+	/** @return list<array<string, mixed>> raw appconfig rows (appid, configkey, configvalue, type, lazy) */
+	private function preserveOwnAppConfig(): array {
+		$qb = $this->db->getQueryBuilder();
+		$qb->select('*')->from('appconfig')
+			->where($qb->expr()->eq('appid', $qb->createNamedParameter(\OCA\NgBackup\AppInfo\Application::APP_ID)));
+		/** @var list<array<string, mixed>> */
+		return $qb->executeQuery()->fetchAll();
+	}
+
+	/**
+	 * @param list<array<string, mixed>> $rows raw appconfig rows, as returned by preserveOwnAppConfig()
+	 *
+	 * Runs in its own transaction (DbDumper::restore() already committed its own by the time
+	 * this is called): not a full guarantee against a crash spanning both, but means this step
+	 * itself cannot leave ng_backup's appconfig rows half deleted, half reinserted.
+	 */
+	private function restoreOwnAppConfig(array $rows): void {
+		$this->db->beginTransaction();
+		try {
+			$qb = $this->db->getQueryBuilder();
+			$qb->delete('appconfig')
+				->where($qb->expr()->eq('appid', $qb->createNamedParameter(\OCA\NgBackup\AppInfo\Application::APP_ID)));
+			$qb->executeStatement();
+			foreach ($rows as $row) {
+				$ins = $this->db->getQueryBuilder();
+				$ins->insert('appconfig')->values([
+					'appid' => $ins->createNamedParameter($row['appid']),
+					'configkey' => $ins->createNamedParameter($row['configkey']),
+					'configvalue' => $ins->createNamedParameter($row['configvalue']),
+					'type' => $ins->createNamedParameter($row['type'], \OCP\DB\QueryBuilder\IQueryBuilder::PARAM_INT),
+					'lazy' => $ins->createNamedParameter($row['lazy'], \OCP\DB\QueryBuilder\IQueryBuilder::PARAM_INT),
+				]);
+				$ins->executeStatement();
+			}
+			$this->db->commit();
+		} catch (\Throwable $e) {
+			$this->db->rollBack();
+			throw $e;
+		}
+	}
+
+	private function rmrf(string $dir): void {
+		if (!is_dir($dir)) {
+			return;
+		}
+		foreach (new \RecursiveIteratorIterator(new \RecursiveDirectoryIterator($dir, \FilesystemIterator::SKIP_DOTS), \RecursiveIteratorIterator::CHILD_FIRST) as $f) {
+			$f->isDir() ? rmdir($f->getPathname()) : unlink($f->getPathname());
+		}
+		rmdir($dir);
+	}
+
+	private function describeBlockers(array $check): string {
+		$parts = [];
+		if ($check['currentMajor'] !== $check['snapshotMajor']) {
+			$parts[] = "this installation is Nextcloud {$check['currentMajor']}, the backup is from {$check['snapshotMajor']} (same major version required)";
+		}
+		if (($check['prefixMismatch'] ?? null) !== null) {
+			[$source, $here] = $check['prefixMismatch'];
+			$parts[] = "the backup's tables use the prefix '$source', this installation '$here': install Nextcloud again with 'dbtableprefix' => '$source' in config/config.php before occ maintenance:install, and restore again";
+		}
+		if ($check['missingTables'] !== []) {
+			$prefix = $this->config->getSystemValueString('dbtableprefix', 'oc_');
+			$parts[] = DbDumper::describeMissing($check['missingTables'], $prefix);
+		}
+		return implode("\n", $parts);
+	}
+
+	private function withSharedLock(Target $target, callable $fn): mixed {
+		try {
+			// Refreshed during the database and data restore (per row batch, per blob), so a
+			// cleanup cannot take over the location while a long restore is still reading it.
+			return $this->leases->with(PruneService::lockKey($target), LeaseService::SHARED, 7200, $fn);
+		} catch (LockedException) {
+			throw new \RuntimeException('A cleanup of ' . $target->getName() . ' is in progress; try again later');
+		}
+	}
+}

lib/Service/RestoreService.php

@@ -33,6 +33,9 @@ final class RestoreService {
 	public const MODE_MERGE = 'merge';
 	public const MODE_REPLACE = 'replace';
 
+	/** @var array<string, true> folders of the current restore already cleared of stale temporaries */
+	private array $cleaned = [];
+
 	public function __construct(
 		private TargetService $targets,
 		private IRootFolder $root,
@@ -81,8 +84,8 @@ final class RestoreService {
 	 *
 	 * @return array{restored:int, trashed:int, target:string}
 	 */
-	public function restoreUserFiles(Target $target, string $snapshotId, string $logicalPath, string $mode = self::MODE_NEW_FOLDER, ?callable $progress = null): array {
-		return $this->withSharedLock($target, function (callable $refresh) use ($target, $snapshotId, $logicalPath, $mode, $progress) {
+	public function restoreUserFiles(Target $target, string $snapshotId, string $logicalPath, string $mode = self::MODE_NEW_FOLDER, ?callable $progress = null, ?array &$skipped = null): array {
+		return $this->withSharedLock($target, function (callable $refresh) use ($target, $snapshotId, $logicalPath, $mode, $progress, &$skipped) {
 			$last = time();
 			// Keep the lease alive while files are being written.
 			$beat = function (int $done, int $total, string $name) use ($refresh, $progress, &$last): void {
@@ -94,11 +97,12 @@ final class RestoreService {
 					$progress($done, $total, $name);
 				}
 			};
-			return $this->doRestoreUserFiles($target, $snapshotId, $logicalPath, $mode, $beat);
+			return $this->doRestoreUserFiles($target, $snapshotId, $logicalPath, $mode, $beat, $skipped);
 		});
 	}
 
-	private function doRestoreUserFiles(Target $target, string $snapshotId, string $logicalPath, string $mode, ?callable $progress): array {
+	/** @param array<string, string>|null $skipped see Repository::restore() */
+	private function doRestoreUserFiles(Target $target, string $snapshotId, string $logicalPath, string $mode, ?callable $progress, ?array &$skipped): array {
 		if (!Repository::isSafePath($logicalPath) || !preg_match('#^data/([^/]+)/files(?:/(.*))?$#', $logicalPath, $m)) {
 			throw new \InvalidArgumentException('Expected a path like data/<user>/files/<folder or file>');
 		}
@@ -133,9 +137,19 @@ final class RestoreService {
 		$dest = $this->ensureFolder($userFolder, $parentRel);
 		$names = $single ? [basename($rel) => $entries['']] : $entries;
 
+		$this->cleaned = [];
 		$restored = 0;
 		foreach ($names as $relPath => $entry) {
-			$this->writeFile($repo, $dest, (string)$relPath, $entry);
+			try {
+				$this->writeFile($repo, $dest, (string)$relPath, $entry);
+			} catch (\OCA\NgBackup\Repository\RepositoryException|\OCA\NgBackup\Backend\BackendException|\OCA\NgBackup\Crypto\CryptoException $e) {
+				// Damaged or missing on the location (writeFile removed its temporary)
+				if ($skipped === null) {
+					throw $e;
+				}
+				$skipped[$entry['p']] = $e->getMessage();
+				continue;
+			}
 			$restored++;
 			if ($progress !== null) {
 				$progress($restored, count($names), (string)$relPath);
@@ -149,20 +163,42 @@ final class RestoreService {
 		return ['restored' => $restored, 'trashed' => $trashed, 'target' => $uid . ':' . $userFolder->getRelativePath($dest->getPath())];
 	}
 
-	/** Raw restore of any snapshot path to a local directory (administrators, disaster recovery). */
-	public function restoreToDirectory(Target $target, string $snapshotId, string $prefix, string $directory): int {
+	/**
+	 * Raw restore of any snapshot path to a local directory (administrators, disaster recovery).
+	 *
+	 * @param bool $stripPrefix write into $directory itself instead of $directory/$prefix (see
+	 *             Repository::restore()); used to restore "data/" or "config/" straight into the
+	 *             real data/config directory for occ backup:restore:full.
+	 * @param bool $keepUnchanged leave files already in place with the snapshot's size and
+	 *             modification time (see Repository::restore()): a full restore that runs again
+	 *             goes on where it stopped
+	 */
+	public function restoreToDirectory(Target $target, string $snapshotId, string $prefix, string $directory, bool $stripPrefix = false, ?callable $heartbeat = null, ?array &$skipped = null, bool $keepUnchanged = false): int {
 		if ($prefix !== '' && !Repository::isSafePath($prefix)) {
 			throw new \InvalidArgumentException('Invalid path: ' . $prefix);
 		}
 		if (!is_dir($directory) && !mkdir($directory, 0750, true) && !is_dir($directory)) {
 			throw new \RuntimeException("Cannot create $directory");
 		}
-		return $this->withSharedLock($target, fn () => $this->targets->repository($target)->restore($snapshotId, $directory, trim($prefix, '/') === '' ? '' : trim($prefix, '/') . '/'), 3600);
+		return $this->withSharedLock($target, function (callable $refresh) use ($target, $snapshotId, $prefix, $directory, $stripPrefix, $heartbeat, &$skipped, $keepUnchanged): int {
+			$own = LeaseService::throttled($refresh);
+			$beat = static function () use ($own, $heartbeat): void {
+				$own();
+				if ($heartbeat !== null) {
+					$heartbeat();
+				}
+			};
+			return $this->targets->repository($target)->restore($snapshotId, $directory, trim($prefix, '/') === '' ? '' : trim($prefix, '/') . '/', $stripPrefix, $beat, $skipped, $keepUnchanged);
+		}, 3600);
 	}
 
 	private function writeFile(Repository $repo, Folder $dest, string $relPath, array $entry): void {
 		$dir = dirname($relPath);
 		$folder = $dir === '.' ? $dest : $this->ensureFolder($dest, $dir);
+		if (!isset($this->cleaned[$folder->getPath()])) {
+			$this->removeStaleTemporaries($folder);
+			$this->cleaned[$folder->getPath()] = true;
+		}
 		$name = basename($relPath);
 		// Stage under a temporary name; only rename into place after every blob was verified.
 		$tmpName = '.' . $name . '.ngb-restore-' . bin2hex(random_bytes(3));
@@ -180,7 +216,7 @@ final class RestoreService {
 				throw new \RuntimeException('Write failed for ' . $relPath);
 			}
 			if ($written !== $entry['s']) {
-				throw new \RuntimeException("Size mismatch restoring $relPath");
+				throw new \OCA\NgBackup\Repository\RepositoryException("Size mismatch restoring $relPath");
 			}
 			if ($folder->nodeExists($name)) {
 				$existing = $folder->get($name);
@@ -208,6 +244,19 @@ final class RestoreService {
 		}
 	}
 
+	/** See Repository::removeStaleTemporaries(): what a restore that was stopped left in this folder. */
+	private function removeStaleTemporaries(Folder $folder): void {
+		foreach ($folder->getDirectoryListing() as $node) {
+			if ($node instanceof File && Repository::isRestoreTemporary($node->getName())) {
+				try {
+					$node->delete();
+				} catch (\Throwable) {
+					// in the way of nothing: the new temporary gets a name of its own
+				}
+			}
+		}
+	}
+
 	private function trashExtras(Folder $folder, string $prefix, array $keep): int {
 		$count = 0;
 		foreach ($folder->getDirectoryListing() as $node) {

lib/Service/Schedule.php

@@ -0,0 +1,110 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\Service;
+
+use OCA\NgBackup\AppInfo\Application;
+use OCP\IAppConfig;
+use OCP\IConfig;
+use OCP\IGroupManager;
+
+/**
+ * The daily backup time: "HH:MM" in a time zone. Nextcloud runs PHP in UTC, so a time without a
+ * zone meant UTC (issue #19: 03:00 ran at 05:00 in Berlin). A time saved before there was a zone
+ * is converted once to the zone of the server or of an administrator, at today's offset: it then
+ * shows as it effectively ran (02:30 UTC becomes 04:30 Europe/Berlin in summer).
+ */
+final class Schedule {
+	public const TIME_KEY = 'schedule_time';
+	public const ZONE_KEY = 'schedule_timezone';
+
+	public function __construct(
+		private IAppConfig $appConfig,
+		private IConfig $config,
+		private IGroupManager $groups,
+	) {
+	}
+
+	/** @return array{time: string, timezone: non-empty-string} time "" = no schedule */
+	public function get(): array {
+		$time = $this->appConfig->getValueString(Application::APP_ID, self::TIME_KEY, '');
+		$zone = $this->appConfig->getValueString(Application::APP_ID, self::ZONE_KEY, '');
+		if ($zone === '' || !self::validZone($zone)) {
+			$zone = $this->guessZone();
+			if ($time !== '' && self::validTime($time)) {
+				$time = self::convert($time, 'UTC', $zone);
+				$this->appConfig->setValueString(Application::APP_ID, self::TIME_KEY, $time);
+			}
+			$this->appConfig->setValueString(Application::APP_ID, self::ZONE_KEY, $zone);
+		}
+		return ['time' => $time, 'timezone' => $zone];
+	}
+
+	/** @throws \InvalidArgumentException for a malformed time or an unknown zone */
+	public function set(string $time, string $zone): void {
+		if ($time !== '' && !self::validTime($time)) {
+			throw new \InvalidArgumentException('Use HH:MM or empty');
+		}
+		if (!self::validZone($zone)) {
+			throw new \InvalidArgumentException('Unknown time zone: ' . $zone);
+		}
+		$this->appConfig->setValueString(Application::APP_ID, self::ZONE_KEY, $zone);
+		$this->appConfig->setValueString(Application::APP_ID, self::TIME_KEY, $time);
+	}
+
+	/** Today's scheduled moment as a Unix time, in the schedule's zone; null without a schedule. */
+	public function todayAt(?int $now = null): ?int {
+		['time' => $time, 'timezone' => $zone] = $this->get();
+		if ($time === '' || !self::validTime($time)) {
+			return null;
+		}
+		$tz = new \DateTimeZone($zone);
+		$day = (new \DateTimeImmutable('@' . ($now ?? time())))->setTimezone($tz)->format('Y-m-d');
+		return (new \DateTimeImmutable($day . ' ' . $time, $tz))->getTimestamp();
+	}
+
+	/**
+	 * "HH:MM" in zone $from as "HH:MM" in zone $to, at today's offsets.
+	 *
+	 * @param non-empty-string $from
+	 * @param non-empty-string $to
+	 */
+	public static function convert(string $time, string $from, string $to, ?int $now = null): string {
+		$day = (new \DateTimeImmutable('@' . ($now ?? time())))->setTimezone(new \DateTimeZone($from))->format('Y-m-d');
+		return (new \DateTimeImmutable($day . ' ' . $time, new \DateTimeZone($from)))->setTimezone(new \DateTimeZone($to))->format('H:i');
+	}
+
+	public static function validTime(string $time): bool {
+		return preg_match('/^([01]\d|2[0-3]):[0-5]\d$/', $time) === 1;
+	}
+
+	/** @psalm-assert-if-true non-empty-string $zone */
+	public static function validZone(string $zone): bool {
+		return in_array($zone, \DateTimeZone::listIdentifiers(), true);
+	}
+
+	/**
+	 * The server's default_timezone when set, else the first administrator's, else UTC. A server
+	 * zone of UTC is passed over on purpose: it is mostly what an image or installer left there,
+	 * while the administrator who set the time read it as their own (#19).
+	 *
+	 * @return non-empty-string
+	 */
+	private function guessZone(): string {
+		$zone = $this->config->getSystemValueString('default_timezone', '');
+		if ($zone !== '' && $zone !== 'UTC' && self::validZone($zone)) {
+			return $zone;
+		}
+		foreach ($this->groups->get('admin')?->getUsers() ?? [] as $user) {
+			$zone = $this->config->getUserValue($user->getUID(), 'core', 'timezone', '');
+			if ($zone !== '' && self::validZone($zone)) {
+				return $zone;
+			}
+		}
+		return 'UTC';
+	}
+}

lib/Service/TargetService.php

@@ -10,10 +10,14 @@ namespace OCA\NgBackup\Service;
 use OCA\NgBackup\Backend\ExternalStorageFactory;
 use OCA\NgBackup\Backend\IBackend;
 use OCA\NgBackup\Backend\StorageBackend;
+use OCA\NgBackup\Db\Snapshot;
+use OCA\NgBackup\Db\SnapshotMapper;
 use OCA\NgBackup\Db\Target;
 use OCA\NgBackup\Db\TargetMapper;
 use OCA\NgBackup\Repository\Repository;
 use OCP\App\IAppManager;
+use OCP\AppFramework\Db\DoesNotExistException;
+use OCP\Files\Storage\IStorage;
 use OCP\Security\ICrypto;
 use OCP\Server;
 
@@ -30,10 +34,11 @@ final class TargetService {
 		private IAppManager $appManager,
 		private \OCA\NgBackup\Db\DbIndexCache $indexCache,
 		private \OCA\NgBackup\Db\AppConfigCatalogAnchor $anchor,
+		private SnapshotMapper $snapshots,
 	) {
 	}
 
-	/** @return list<array{id:string, name:string, auth:list<string>, parameters:array}> */
+	/** @return list<array{id:string, name:string, auth:list<array{id:string, name:string, parameters:array}>, parameters:array}> */
 	public function availableBackends(): array {
 		return $this->factory()->describeBackends();
 	}
@@ -43,21 +48,16 @@ final class TargetService {
 	 * installation's key), then save it.
 	 *
 	 * @param array<string, mixed> $options
+	 * @param ?callable(int, int): void $progress reading an existing repository's index: files done, and in all
 	 * @return array{target: Target, created: bool}
 	 */
-	public function add(string $name, string $backend, string $auth, array $options, string $basePath): array {
-		if (!preg_match('/^[A-Za-z0-9][A-Za-z0-9 _.-]{0,63}$/', $name)) {
-			throw new \InvalidArgumentException('Name: letters, digits, space, _ . - (max 64)');
-		}
-		try {
-			$this->mapper->findByName($name);
-			throw new \InvalidArgumentException("A target named '$name' already exists");
-		} catch (\OCP\AppFramework\Db\DoesNotExistException) {
-		}
+	public function add(string $name, string $backend, string $auth, array $options, string $basePath, ?callable $progress = null): array {
+		$this->validateName($name);
+		$this->requireUsableBackend($backend);
 		$keys = $this->keys->keyRing();
 		$storageBackend = $this->buildBackend($backend, $auth, $options, $basePath);
 		if ($storageBackend->exists('config')) {
-			$repo = Repository::openWithKey($storageBackend, $keys, $this->indexCache, $this->anchor);
+			$repo = Repository::openWithKey($storageBackend, $keys, $this->indexCache, $this->anchor, $progress);
 			$created = false;
 		} else {
 			$repo = Repository::initWithKey($storageBackend, $keys, $this->keys->wrappedKey(), $this->anchor);
@@ -78,7 +78,160 @@ final class TargetService {
 		$target->setBasePath(trim($basePath, '/'));
 		$target->setRepositoryId($repo->id());
 		$target->setCreatedAt(time());
-		return ['target' => $this->mapper->insert($target), 'created' => $created];
+		$target = $this->mapper->insert($target);
+		if (!$created) {
+			// Disaster recovery: occ backup:list reads this local cache, not the repository
+			// directly, so a snapshot made by another installation must be backfilled here too.
+			$this->adoptSnapshots($target, $repo);
+		}
+		return ['target' => $target, 'created' => $created];
+	}
+
+	/**
+	 * Change how an existing location is reached (credentials, host, folder, even the connection
+	 * type) or its name. The new settings must lead to the same repository: the history stays
+	 * and a typo cannot silently start a new, empty repository. A null option value keeps the
+	 * stored one, so the web interface never has to send stored passwords back.
+	 *
+	 * @param array<string, mixed> $options
+	 */
+	public function update(Target $target, string $name, string $backend, string $auth, array $options, string $basePath): Target {
+		$this->validateName($name, $target->getId());
+		$this->requireUsableBackend($backend);
+		$stored = $this->options($target);
+		foreach ($options as $key => $value) {
+			if ($value === null) {
+				if (array_key_exists($key, $stored)) {
+					$options[$key] = $stored[$key];
+				} else {
+					unset($options[$key]);
+				}
+			}
+		}
+		// Do not create the folder: a typo in the path must not leave an empty folder behind.
+		$storageBackend = $this->buildBackend($backend, $auth, $options, $basePath, false);
+		if (!$storageBackend->exists('config')) {
+			if (!$storageBackend->canConnect()) {
+				throw new \InvalidArgumentException('Cannot connect with these settings. Check the host, user name and password');
+			}
+			throw new \InvalidArgumentException("No NG Backup repository found in folder '" . trim($basePath, '/') . "'. To start an empty repository, add a new location instead");
+		}
+		$repo = Repository::openWithKey($storageBackend, $this->keys->keyRing(), $this->indexCache, $this->anchor);
+		if ($target->getRepositoryId() !== null && $repo->id() !== $target->getRepositoryId()) {
+			throw new \InvalidArgumentException('These settings lead to a different repository than the one of this location');
+		}
+		$target->setName($name);
+		$target->setBackend($backend);
+		$target->setAuth($auth);
+		$target->setOptions($this->crypto->encrypt(json_encode($options, JSON_THROW_ON_ERROR)));
+		$target->setBasePath(trim($basePath, '/'));
+		return $this->mapper->update($target);
+	}
+
+	/**
+	 * The stored options for an edit form: password-type values are replaced by null, which
+	 * update() reads as "keep the stored value".
+	 *
+	 * @return array<string, mixed>
+	 */
+	public function editableOptions(Target $target): array {
+		$secret = [];
+		foreach ($this->availableBackends() as $b) {
+			if ($b['id'] !== $target->getBackend()) {
+				continue;
+			}
+			$params = $b['parameters'];
+			foreach ($b['auth'] as $a) {
+				if ($a['id'] === $target->getAuth()) {
+					$params += $a['parameters'];
+				}
+			}
+			foreach ($params as $key => $p) {
+				if (($p['type'] ?? 0) === 2) {
+					$secret[$key] = true;
+				}
+			}
+		}
+		$options = $this->options($target);
+		foreach ($options as $key => $value) {
+			if (isset($secret[$key])) {
+				$options[$key] = null;
+			}
+		}
+		return $options;
+	}
+
+	private function validateName(string $name, ?int $ownId = null): void {
+		if (!preg_match('/^[A-Za-z0-9][A-Za-z0-9 _.-]{0,63}$/', $name)) {
+			throw new \InvalidArgumentException('Name: letters, digits, space, _ . - (max 64)');
+		}
+		try {
+			$other = $this->mapper->findByName($name);
+		} catch (DoesNotExistException) {
+			return;
+		}
+		if ($other->getId() !== $ownId) {
+			throw new \InvalidArgumentException("A target named '$name' already exists");
+		}
+	}
+
+	private function requireUsableBackend(string $backend): void {
+		// Without the native extension files_external falls back to the smbclient binary, which
+		// registers fine but cannot seek: the first backup then fails with "Seek failed". Refuse
+		// up front instead of letting the admin find out from a failed run.
+		if ($backend === 'smb' && !extension_loaded('smbclient')) {
+			throw new \InvalidArgumentException('The SMB backend needs the PHP smbclient extension (pecl install smbclient); the smbclient binary alone cannot seek and every backup would fail');
+		}
+	}
+
+	/**
+	 * A target's options are encrypted with Nextcloud's own instance secret (ICrypto), not
+	 * ng_backup's key, so changing that secret (occ backup:restore:full merging config.php)
+	 * would otherwise leave every target permanently undecryptable. Call $applySecretChange
+	 * (which must be the only thing that changes the secret) through here instead: every
+	 * target's options are decrypted first, then re-encrypted under whatever secret is active
+	 * once $applySecretChange returns.
+	 */
+	public function reencryptOptionsAround(callable $applySecretChange): mixed {
+		$plain = [];
+		foreach ($this->mapper->findAll() as $target) {
+			$plain[$target->getId()] = $this->options($target);
+		}
+		$result = $applySecretChange();
+		foreach ($this->mapper->findAll() as $target) {
+			if (!isset($plain[$target->getId()])) {
+				continue; // added by $applySecretChange itself; nothing to re-encrypt
+			}
+			$target->setOptions($this->crypto->encrypt(json_encode($plain[$target->getId()], JSON_THROW_ON_ERROR)));
+			$this->mapper->update($target);
+		}
+		return $result;
+	}
+
+	private function adoptSnapshots(Target $target, Repository $repo): void {
+		foreach ($repo->listSnapshots() as $snapshotId) {
+			try {
+				$this->snapshots->findOne($target->getId(), $snapshotId);
+				continue; // already known locally
+			} catch (DoesNotExistException) {
+			}
+			// One unreadable/corrupt snapshot must not stop the rest of the location's
+			// snapshots from being backfilled, nor abort adding the target itself.
+			try {
+				$meta = $repo->snapshotMeta($snapshotId);
+				$s = new Snapshot();
+				$s->setTargetId($target->getId());
+				$s->setSnapshotId($snapshotId);
+				$s->setKind((string)($meta['kind'] ?? 'full'));
+				$s->setLabel(($meta['label'] ?? '') !== '' ? $meta['label'] : null);
+				$s->setCreatedAt((int)strtotime((string)($meta['time'] ?? 'now')));
+				$s->setFiles((int)($meta['stats']['files'] ?? 0));
+				$s->setBytes((int)($meta['stats']['bytes'] ?? 0));
+				$this->snapshots->insert($s);
+			} catch (\Throwable $e) {
+				Server::get(\Psr\Log\LoggerInterface::class)->warning('NG Backup: snapshot ' . $snapshotId . ' on ' . $target->getName() . ' not listed: ' . $e->getMessage(), ['exception' => $e]);
+			}
+		}
 	}
 
 	/** @return list<Target> */
@@ -87,7 +240,11 @@ final class TargetService {
 	}
 
 	public function get(string $nameOrId): Target {
-		return ctype_digit($nameOrId) ? $this->mapper->find((int)$nameOrId) : $this->mapper->findByName($nameOrId);
+		try {
+			return ctype_digit($nameOrId) ? $this->mapper->find((int)$nameOrId) : $this->mapper->findByName($nameOrId);
+		} catch (DoesNotExistException) {
+			throw new \InvalidArgumentException("No such location: $nameOrId");
+		}
 	}
 
 	/** Size limit for the data stored on this location (null = none). */
@@ -104,6 +261,11 @@ final class TargetService {
 	/** Remove the target from NG Backup. The backups on the target itself are not touched. */
 	public function remove(Target $target): void {
 		$this->mapper->delete($target);
+		// The cached index of its repository is only of use while a location points at it
+		$repositoryId = $target->getRepositoryId();
+		if ($repositoryId !== null && !array_filter($this->list(), fn (Target $t) => $t->getRepositoryId() === $repositoryId)) {
+			$this->indexCache->forget($repositoryId);
+		}
 	}
 
 	public function backend(Target $target): IBackend {
@@ -124,8 +286,12 @@ final class TargetService {
 		return json_decode($this->crypto->decrypt($target->getOptions()), true, 512, JSON_THROW_ON_ERROR);
 	}
 
-	private function buildBackend(string $backend, string $auth, array $options, string $basePath): StorageBackend {
-		return new StorageBackend($this->factory()->create($backend, $auth, $options), $basePath);
+	private function buildBackend(string $backend, string $auth, array $options, string $basePath, bool $createBase = true): StorageBackend {
+		$create = fn (): IStorage => $this->factory()->create($backend, $auth, $options);
+		$storage = new StorageBackend($create(), $basePath, $createBase, $create);
+		$storage->readAheadConnections = Server::get(\OCP\IAppConfig::class)
+			->getValueInt('ng_backup', 'restore_sftp_connections', \OCA\NgBackup\Backend\SftpRangeFetcher::DEFAULT_CONNECTIONS);
+		return $storage;
 	}
 
 	private ?ExternalStorageFactory $factory = null;

lib/Service/UserBackupService.php

@@ -0,0 +1,66 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\Service;
+
+use OCA\NgBackup\Db\Target;
+use OCA\NgBackup\UserMigration\RepositoryExportDestination;
+use OCA\NgBackup\UserMigration\UserMigrationServiceLocator;
+use OCP\IUser;
+use OCP\Lock\LockedException;
+use OCP\UserMigration\UserMigrationException;
+
+/**
+ * Per-user backup via user_migration: every registered migrator's export streams straight into
+ * the encrypted repository (no zip, no copy in the user's own storage, see
+ * RepositoryExportDestination). Shares blobs with the full backup; prune() keeps a user export's
+ * blobs referenced through its manifest under users/<uid>/.
+ *
+ * user_migration is an optional dependency (unlike files_external): without it, only this
+ * per-user backup/restore is unavailable, the full backup still works.
+ */
+final class UserBackupService {
+	public function __construct(
+		private TargetService $targets,
+		private LeaseService $leases,
+		private UserMigrationServiceLocator $locator,
+	) {
+	}
+
+	/** @throws UserMigrationException when user_migration is not enabled, or the export itself fails */
+	public function backupUser(Target $target, IUser $user): string {
+		$service = $this->locator->get();
+		return $this->withSharedLock($target, function (callable $refresh) use ($target, $user, $service) {
+			$repo = $this->targets->repository($target);
+			$dest = new RepositoryExportDestination($repo, $user->getUID(), LeaseService::throttled($refresh));
+			$service->export($dest, $user);
+			// A short exclusive lock around the catalog write only: the shared lock above
+			// allows another concurrent backup (full or per-user) to be writing the catalog at
+			// the same time. The repository is reopened inside the lock, so the write builds on
+			// the latest catalog generation instead of the one loaded before the lock was taken.
+			$this->withCatalogLock($target, fn () => $this->targets->repository($target)->recordUserExport($dest->manifestPath()));
+			return $dest->manifestPath();
+		});
+	}
+
+	private function withSharedLock(Target $target, callable $fn): mixed {
+		try {
+			// Refreshed by RepositoryExportDestination as it writes data, so a long export keeps it.
+			return $this->leases->with(PruneService::lockKey($target), LeaseService::SHARED, 3600, $fn);
+		} catch (LockedException) {
+			throw new \RuntimeException('A cleanup of ' . $target->getName() . ' is in progress; try again later');
+		}
+	}
+
+	private function withCatalogLock(Target $target, callable $fn): mixed {
+		try {
+			return $this->leases->with(PruneService::catalogLockKey($target), LeaseService::EXCLUSIVE, 300, $fn);
+		} catch (LockedException) {
+			throw new \RuntimeException('Another catalog write for ' . $target->getName() . ' is in progress; try again');
+		}
+	}
+}

lib/Service/UserRestoreService.php

@@ -0,0 +1,137 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\Service;
+
+use OCA\NgBackup\Db\Target;
+use OCA\NgBackup\UserMigration\RepositoryExportDestination;
+use OCA\NgBackup\UserMigration\RepositoryImportSource;
+use OCA\NgBackup\UserMigration\UserMigrationServiceLocator;
+use OCP\EventDispatcher\IEventDispatcher;
+use OCP\Files\Events\Node\FilesystemTornDownEvent;
+use OCP\IUser;
+use OCP\IUserManager;
+use OCP\Lock\LockedException;
+use OCP\Security\ISecureRandom;
+use OCP\UserMigration\UserMigrationException;
+
+/**
+ * Restoring a user from a user_migration export (see UserBackupService), never over an existing
+ * account:
+ *  - replace: a safety export of the current state goes into the repository first, then the
+ *    account is deleted and recreated fresh from the backup, under the same uid;
+ *  - as-backup: the backup is restored into a new account "<uid>-bak" (or "-bak-2", ...) instead,
+ *    so an admin can compare and transfer by hand. Nextcloud cannot rename a uid, so the *backup*
+ *    gets the new name, never the existing account.
+ */
+final class UserRestoreService {
+	public const MODE_REPLACE = 'replace';
+	public const MODE_AS_BACKUP = 'as-backup';
+
+	public function __construct(
+		private TargetService $targets,
+		private LeaseService $leases,
+		private UserMigrationServiceLocator $locator,
+		private IUserManager $userManager,
+		private ISecureRandom $random,
+		private IEventDispatcher $events,
+	) {
+	}
+
+	/** @throws UserMigrationException when user_migration is not enabled, or the restore itself fails */
+	public function restoreUser(Target $target, string $manifestPath, string $mode = self::MODE_REPLACE): IUser {
+		$service = $this->locator->get();
+		return $this->withSharedLock($target, function (callable $refresh) use ($target, $manifestPath, $mode, $service): IUser {
+			$repo = $this->targets->repository($target);
+			// Only ever read a manifest the verified catalog actually recorded: a path alone
+			// (even one this app generated before) proves nothing about it still being current
+			// or genuine once the catalog's rollback protection is supposed to vouch for it.
+			if (!$repo->isRecordedUserExport($manifestPath)) {
+				throw new \InvalidArgumentException("$manifestPath is not a recorded user export for this location");
+			}
+			$beat = LeaseService::throttled($refresh);
+			$source = new RepositoryImportSource($repo, $manifestPath, $beat);
+			$originalUid = $source->getOriginalUid();
+
+			if ($mode === self::MODE_AS_BACKUP) {
+				$backupUid = $this->freeBackupUid($originalUid);
+				$user = $this->userManager->createUser($backupUid, $this->random->generate(32));
+				if ($user === false) {
+					throw new \RuntimeException("Could not create the account $backupUid");
+				}
+				try {
+					return $service->import($source, $user);
+				} catch (\Throwable $e) {
+					// A partially-imported, never-used account left behind is strictly worse
+					// than no account at all; the original source account was never touched.
+					$user->delete();
+					throw $e;
+				}
+			}
+
+			if ($mode !== self::MODE_REPLACE) {
+				throw new \InvalidArgumentException("Unknown restore mode: $mode");
+			}
+			$existing = $this->userManager->get($originalUid);
+			$safetyManifestPath = null;
+			if ($existing !== null) {
+				// Never import over a live account: export its current state first, so nothing
+				// is lost if the restore turns out to be the wrong choice.
+				$safety = new RepositoryExportDestination($repo, $originalUid, $beat);
+				$service->export($safety, $existing);
+				$safetyManifestPath = $safety->manifestPath();
+				// Same race as UserBackupService::backupUser(): reopen the repository inside the
+				// catalog lock so the write builds on the latest generation.
+				$this->withCatalogLock($target, fn () => $this->targets->repository($target)->recordUserExport($safetyManifestPath));
+				if (!$existing->delete()) {
+					throw new \RuntimeException("Could not delete the existing account $originalUid before restoring; its safety export is at $safetyManifestPath");
+				}
+				// IRootFolder caches a Folder per uid for the lifetime of this process; without
+				// this it would still hand the just-deleted account's (now storage-less) folder
+				// to the import below, and every write would fail.
+				$this->events->dispatchTyped(new FilesystemTornDownEvent());
+			}
+			try {
+				return $service->import($source, null);
+			} catch (\Throwable $e) {
+				// The original account is already gone at this point (or never existed); a
+				// failure here can only be reported, not undone in place. Its safety export
+				// (if any) is the recovery path, already recorded above.
+				throw new UserMigrationException(
+					"Could not restore $originalUid" . ($safetyManifestPath !== null ? "; its safety export is at $safetyManifestPath" : '') . ': ' . $e->getMessage(),
+					0,
+					$e,
+				);
+			}
+		});
+	}
+
+	private function freeBackupUid(string $uid): string {
+		$candidate = $uid . '-bak';
+		for ($n = 2; $this->userManager->userExists($candidate); $n++) {
+			$candidate = $uid . '-bak-' . $n;
+		}
+		return $candidate;
+	}
+
+	private function withSharedLock(Target $target, callable $fn): mixed {
+		try {
+			// Refreshed while the safety export writes and the import reads (see UserBackupService::withSharedLock()).
+			return $this->leases->with(PruneService::lockKey($target), LeaseService::SHARED, 3600, $fn);
+		} catch (LockedException) {
+			throw new \RuntimeException('A cleanup of ' . $target->getName() . ' is in progress; try again later');
+		}
+	}
+
+	private function withCatalogLock(Target $target, callable $fn): mixed {
+		try {
+			return $this->leases->with(PruneService::catalogLockKey($target), LeaseService::EXCLUSIVE, 300, $fn);
+		} catch (LockedException) {
+			throw new \RuntimeException('Another catalog write for ' . $target->getName() . ' is in progress; try again');
+		}
+	}
+}

lib/Service/VerifyService.php

@@ -0,0 +1,158 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\Service;
+
+use OCA\NgBackup\AppInfo\Application;
+use OCA\NgBackup\Db\Target;
+use OCP\IAppConfig;
+use OCP\Lock\LockedException;
+
+/**
+ * Checksum audit of a snapshot (occ backup:verify), see Repository::verify(). On a large
+ * repository a check takes hours (a deep one days), so how far it is gets stored every
+ * PROGRESS_SECONDS, together with how it ended: `occ backup:status` shows it.
+ */
+final class VerifyService {
+	public const PROGRESS_SECONDS = 30;
+	private const KEY_PREFIX = 'verify_progress_';
+
+	public function __construct(
+		private TargetService $targets,
+		private LeaseService $leases,
+		private IAppConfig $appConfig,
+	) {
+	}
+
+	/**
+	 * @param ?callable(array):void $onProgress called with the stored progress every PROGRESS_SECONDS
+	 * @return array{filesChecked:int, blobsChecked:int, bytesChecked:int, missing:list<string>, failed:list<string>, unreadable:list<string>, readError:string}
+	 */
+	public function verify(Target $target, string $snapshotId, bool $deep = false, ?callable $onProgress = null): array {
+		return $this->run($target, $snapshotId, $deep, $onProgress, fn (\OCA\NgBackup\Repository\Repository $repo, callable $heartbeat): array => $repo->verify($snapshotId, $deep, $heartbeat));
+	}
+
+	/**
+	 * @param ?callable(array):void $onProgress called with the stored progress every PROGRESS_SECONDS
+	 * @return array{filesChecked:int, blobsChecked:int, bytesChecked:int, missing:list<string>, failed:list<string>, unreadable:list<string>, readError:string}
+	 */
+	public function verifyUserExport(Target $target, string $manifestPath, bool $deep = false, ?callable $onProgress = null): array {
+		return $this->run($target, $manifestPath, $deep, $onProgress, fn (\OCA\NgBackup\Repository\Repository $repo, callable $heartbeat): array => $repo->verifyUserExport($manifestPath, $deep, $heartbeat));
+	}
+
+	/** One line on a check's progress or outcome, for occ (see progress()). */
+	public static function describe(array $s): string {
+		$size = static fn (int $b): string => $b >= 1073741824 ? sprintf('%.1f GiB', (float)$b / 1073741824.0) : sprintf('%.1f MiB', (float)$b / 1048576.0);
+		$count = static fn (int $done, mixed $total): string => number_format($done)
+			. (is_int($total) && $total > 0 ? '/' . number_format($total) . sprintf(' (%d%%)', intdiv(100 * $done, $total)) : '');
+		$deep = ($s['deep'] ?? false) === true;
+		$kind = $deep ? 'deep check' : 'check';
+		if (($s['status'] ?? '') === 'running') {
+			$phase = match ($s['phase'] ?? '') {
+				'index' => 'index files ' . $count((int)$s['done'], $s['total'] ?? null),
+				'packs' => 'pack folders ' . $count((int)$s['done'], $s['total'] ?? null),
+				'files', 'database' => 'files ' . $count((int)$s['done'], $s['total'] ?? null) . ', ' . number_format((int)($s['blobs'] ?? 0)) . ' blobs'
+					. ($deep ? ', ' . $size((int)($s['bytes'] ?? 0)) . ' decrypted' : ''),
+				default => 'starting',
+			};
+			$age = time() - (int)($s['updated'] ?? 0);
+			return sprintf('%s running since %s: %s; updated %s ago%s', $kind, date('Y-m-d H:i', (int)$s['started']), $phase,
+				$age < 120 ? $age . ' s' : intdiv($age, 60) . ' min',
+				$age > 600 ? ' (no progress for a while: the process may have stopped)' : '');
+		}
+		$took = \OCA\NgBackup\Format::duration((int)($s['finished'] ?? 0) - (int)($s['started'] ?? 0));
+		return match ($s['status'] ?? '') {
+			'ok' => sprintf('%s OK on %s (took %s): %s files, %s blobs%s', $kind, date('Y-m-d H:i', (int)$s['finished']), $took,
+				number_format((int)($s['files'] ?? 0)), number_format((int)($s['blobs'] ?? 0)), $deep ? ', ' . $size((int)($s['bytes'] ?? 0)) . ' decrypted' : ''),
+			'problems' => sprintf('%s found PROBLEMS on %s: %d missing, %d failed, %d unreadable blob(s); run occ backup:verify again for the details',
+				$kind, date('Y-m-d H:i', (int)$s['finished']), (int)($s['missing'] ?? 0), (int)($s['failedBlobs'] ?? 0), (int)($s['unreadable'] ?? 0)),
+			default => sprintf('%s FAILED on %s: %s', $kind, date('Y-m-d H:i', (int)($s['finished'] ?? 0)), (string)($s['error'] ?? 'unknown error')),
+		};
+	}
+
+	/**
+	 * The stored state of the last check per location: running (with how far it is) or how it
+	 * ended.
+	 *
+	 * @return array<int, array<string, mixed>> by location id
+	 */
+	public function progress(): array {
+		$result = [];
+		foreach ($this->appConfig->getKeys(Application::APP_ID) as $key) {
+			if (!str_starts_with($key, self::KEY_PREFIX)) {
+				continue;
+			}
+			$state = json_decode($this->appConfig->getValueString(Application::APP_ID, $key, '', lazy: true), true);
+			if (is_array($state)) {
+				$result[(int)substr($key, strlen(self::KEY_PREFIX))] = $state;
+			}
+		}
+		ksort($result);
+		return $result;
+	}
+
+	private function run(Target $target, string $what, bool $deep, ?callable $onProgress, callable $fn): array {
+		$ttl = $deep ? 600 : 300;
+		$state = ['what' => $what, 'deep' => $deep, 'status' => 'running', 'started' => time(), 'updated' => time(),
+			'pid' => getmypid(), 'phase' => 'starting', 'done' => 0, 'total' => null, 'blobs' => 0, 'bytes' => 0];
+		try {
+			$this->store($target, $state);
+		} catch (\Throwable) {
+			// progress reports are a convenience; the check itself goes ahead
+		}
+		try {
+			$result = $this->leases->with(PruneService::lockKey($target), LeaseService::SHARED, $ttl, function (callable $refresh) use ($target, $ttl, $fn, $onProgress, &$state): array {
+				$lastRefresh = time();
+				$lastStore = time();
+				$heartbeat = function (?array $progress = null) use ($refresh, $ttl, $target, $onProgress, &$lastRefresh, &$lastStore, &$state): void {
+					$now = time();
+					if ($now - $lastRefresh >= intdiv($ttl, 2)) {
+						$refresh();
+						$lastRefresh = $now;
+					}
+					if ($progress !== null && $now - $lastStore >= self::PROGRESS_SECONDS) {
+						$state = array_merge($state, $progress, ['updated' => $now]);
+						try {
+							$this->store($target, $state);
+						} catch (\Throwable) {
+							// a progress report that cannot be stored must not stop the check
+						}
+						$lastStore = $now;
+						if ($onProgress !== null) {
+							$onProgress($state);
+						}
+					}
+				};
+				return $fn($this->targets->repository($target), $heartbeat);
+			});
+		} catch (LockedException) {
+			$this->finish($target, $state, 'failed', ['error' => 'A cleanup of the location was in progress']);
+			throw new \RuntimeException('A cleanup of ' . $target->getName() . ' is in progress; try again later');
+		} catch (\Throwable $e) {
+			$this->finish($target, $state, 'failed', ['error' => $e->getMessage()]);
+			throw $e;
+		}
+		$problems = count($result['missing']) + count($result['failed']) + count($result['unreadable']);
+		$this->finish($target, $state, $problems === 0 ? 'ok' : 'problems', [
+			'phase' => 'done', 'files' => $result['filesChecked'], 'blobs' => $result['blobsChecked'], 'bytes' => $result['bytesChecked'],
+			'missing' => count($result['missing']), 'failedBlobs' => count($result['failed']), 'unreadable' => count($result['unreadable']),
+		]);
+		return $result;
+	}
+
+	private function finish(Target $target, array $state, string $status, array $extra): void {
+		try {
+			$this->store($target, array_merge($state, $extra, ['status' => $status, 'updated' => time(), 'finished' => time()]));
+		} catch (\Throwable) {
+			// the check's own result counts; its stored summary is a convenience
+		}
+	}
+
+	private function store(Target $target, array $state): void {
+		$this->appConfig->setValueString(Application::APP_ID, self::KEY_PREFIX . $target->getId(), json_encode($state, JSON_THROW_ON_ERROR), lazy: true);
+	}
+}

lib/UserMigration/RepositoryExportDestination.php

@@ -28,6 +28,8 @@ final class RepositoryExportDestination implements IExportDestination {
 	public function __construct(
 		private Repository $repo,
 		private string $uid,
+		/** Called while data is written (per chunk), to keep the location lease alive. */
+		private ?\Closure $heartbeat = null,
 	) {
 		$this->exportId = gmdate('Ymd\THis\Z') . '-' . bin2hex(random_bytes(4));
 	}
@@ -36,6 +38,7 @@ final class RepositoryExportDestination implements IExportDestination {
 		$writer = $this->repo->blobWriter($this->stats);
 		$writer->write($content);
 		$this->entries[self::norm($path)] = ['t' => 'f', 'b' => $writer->finish(), 's' => strlen($content)];
+		$this->beat();
 	}
 
 	public function addFileAsStream(string $path, $stream): void {
@@ -46,6 +49,7 @@ final class RepositoryExportDestination implements IExportDestination {
 				throw new UserMigrationException('Read error while exporting ' . $path);
 			}
 			$writer->write($chunk);
+			$this->beat();
 		}
 		$this->entries[self::norm($path)] = ['t' => 'f', 'b' => $writer->finish(), 's' => $writer->bytes()];
 	}
@@ -65,8 +69,11 @@ final class RepositoryExportDestination implements IExportDestination {
 				if ($stream === false) {
 					throw new \RuntimeException('Cannot read ' . $node->getPath());
 				}
-				$this->addFileAsStream($target, $stream);
-				fclose($stream);
+				try {
+					$this->addFileAsStream($target, $stream);
+				} finally {
+					fclose($stream);
+				}
 			}
 		}
 	}
@@ -89,6 +96,12 @@ final class RepositoryExportDestination implements IExportDestination {
 		return $this->stats;
 	}
 
+	private function beat(): void {
+		if ($this->heartbeat !== null) {
+			($this->heartbeat)();
+		}
+	}
+
 	private static function norm(string $path): string {
 		return trim($path, '/');
 	}

lib/UserMigration/RepositoryImportSource.php

@@ -20,6 +20,8 @@ final class RepositoryImportSource implements IImportSource {
 	public function __construct(
 		private Repository $repo,
 		string $manifestPath,
+		/** Called while blobs are read, to keep the location lease alive. */
+		private ?\Closure $heartbeat = null,
 	) {
 		$this->manifest = json_decode($repo->getObject($manifestPath), true, 512, JSON_THROW_ON_ERROR);
 	}
@@ -40,6 +42,9 @@ final class RepositoryImportSource implements IImportSource {
 			throw new UserMigrationException('Cannot buffer ' . $path);
 		}
 		foreach ($this->repo->readBlobs($entry['b']) as $data) {
+			if ($this->heartbeat !== null) {
+				($this->heartbeat)();
+			}
 			for ($done = 0, $len = strlen($data); $done < $len; $done += $n) {
 				$n = fwrite($stream, $done === 0 ? $data : substr($data, $done));
 				if ($n === false || $n === 0) {
@@ -109,7 +114,14 @@ final class RepositoryImportSource implements IImportSource {
 						$destination->newFile($name, $stream);
 					}
 				} finally {
-					fclose($stream);
+					// putContent()/newFile() already close the stream once they've consumed it:
+					// despite the @return resource docblock above, $stream is no longer a
+					// resource by the time we get here (verified against a real storage; a
+					// double fclose() throws a TypeError on PHP 8).
+					/** @psalm-suppress RedundantConditionGivenDocblockType */
+					if (is_resource($stream)) {
+						fclose($stream);
+					}
 				}
 			}
 		}

lib/UserMigration/UserMigrationInstaller.php

@@ -0,0 +1,77 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\UserMigration;
+
+use OCP\App\AppPathNotFoundException;
+use OCP\App\IAppManager;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+use Symfony\Component\Console\Helper\QuestionHelper;
+use Symfony\Component\Console\Question\ConfirmationQuestion;
+
+/**
+ * Installs or enables the optional user_migration app, but only when the administrator asked for it
+ * (occ prompt or --install-user-migration). Runs occ in a child process, as the admin would.
+ */
+final class UserMigrationInstaller {
+	private const APP = 'user_migration';
+
+	public function __construct(
+		private IAppManager $appManager,
+	) {
+	}
+
+	public function isEnabled(): bool {
+		return $this->appManager->isEnabledForAnyone(self::APP);
+	}
+
+	private function codeIsPresent(): bool {
+		try {
+			$this->appManager->getAppPath(self::APP);
+			return true;
+		} catch (AppPathNotFoundException) {
+			return false;
+		}
+	}
+
+	/** Installs (from the app store, if missing) and enables user_migration; throws on failure. */
+	public function install(): void {
+		$args = $this->codeIsPresent() ? ['app:enable', self::APP] : ['app:install', self::APP];
+		/** @psalm-suppress UndefinedClass */
+		$occ = \OC::$SERVERROOT . '/occ';
+		$command = implode(' ', array_map('escapeshellarg', [PHP_BINARY, $occ, ...$args])) . ' 2>&1';
+		exec($command, $lines, $code);
+		if ($code !== 0) {
+			throw new \RuntimeException("occ " . implode(' ', $args) . " failed:\n" . implode("\n", $lines));
+		}
+	}
+
+	/**
+	 * Returns when user_migration is enabled. Otherwise asks the administrator (interactive shell) or
+	 * requires --install-user-migration, and throws when neither gives consent.
+	 *
+	 * @throws \RuntimeException
+	 */
+	public function ensureEnabled(InputInterface $input, OutputInterface $output): void {
+		if ($this->isEnabled()) {
+			return;
+		}
+		$consent = $input->getOption('install-user-migration') === true;
+		if (!$consent && $input->isInteractive()) {
+			$consent = (new QuestionHelper())->ask($input, $output, new ConfirmationQuestion(
+				'The user_migration app is not enabled. Install and enable it now? [y/N] ', false)) === true;
+		}
+		if (!$consent) {
+			throw new \RuntimeException('The user_migration app is not enabled; per-user backup/restore needs it. Run "occ '
+				. 'app:install ' . self::APP . '" and "occ app:enable ' . self::APP . '", or repeat with --install-user-migration');
+		}
+		$output->writeln('Installing and enabling user_migration (approved by the administrator)...');
+		$this->install();
+		throw new \RuntimeException('user_migration is installed and enabled; run this command again');
+	}
+}

lib/UserMigration/UserMigrationServiceLocator.php

@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\UserMigration;
+
+use OCP\App\IAppManager;
+use OCP\Server;
+use OCP\UserMigration\UserMigrationException;
+
+/**
+ * Resolves user_migration's own (internal, non-public) UserMigrationService on demand.
+ *
+ * Unlike files_external, user_migration is an optional dependency: without it, only per-user
+ * backup/restore is unavailable, the full backup still works. The class is never autoloaded by
+ * composer; everything that touches it is behind this one class.
+ */
+final class UserMigrationServiceLocator {
+	public function __construct(
+		private IAppManager $appManager,
+	) {
+	}
+
+	/** @throws UserMigrationException when user_migration is not enabled anywhere */
+	public function get(): object {
+		if (!$this->appManager->isEnabledForAnyone('user_migration')) {
+			throw new UserMigrationException('The user_migration app is not enabled; per-user backup/restore is unavailable');
+		}
+		$this->appManager->loadApp('user_migration');
+		return Server::get(\OCA\UserMigration\Service\UserMigrationService::class);
+	}
+}

psalm-baseline.xml

@@ -49,6 +49,11 @@
       <code><![CDATA[ask]]></code>
     </UndefinedInterfaceMethod>
   </file>
+  <file src="lib/Command/KeyImport.php">
+    <UndefinedInterfaceMethod>
+      <code><![CDATA[ask]]></code>
+    </UndefinedInterfaceMethod>
+  </file>
   <file src="lib/Command/KeyInit.php">
     <UndefinedInterfaceMethod>
       <code><![CDATA[ask]]></code>
@@ -105,11 +110,6 @@
       <code><![CDATA[ask]]></code>
     </UndefinedInterfaceMethod>
   </file>
-  <file src="lib/Command/Trash.php">
-    <RedundantCastGivenDocblockType>
-      <code><![CDATA[(string)($info['time'] ?? '')]]></code>
-    </RedundantCastGivenDocblockType>
-  </file>
   <file src="lib/Controller/AdminApiController.php">
     <InvalidOperand>
       <code><![CDATA[$maxGb * 1073741824]]></code>
@@ -148,10 +148,6 @@
     </PossiblyFalseArgument>
   </file>
   <file src="lib/Db/DbDumper.php">
-    <InvalidArrayOffset>
-      <code><![CDATA[$info['sha256']]]></code>
-      <code><![CDATA[$manifest['sequences']]]></code>
-    </InvalidArrayOffset>
     <MissingClosureReturnType>
       <code><![CDATA[fn ($c) => $end[array_search($c, $columns, true)]]]></code>
       <code><![CDATA[fn ($c) => $q($c)]]></code>
@@ -184,6 +180,12 @@
       <code><![CDATA[$this->db]]></code>
       <code><![CDATA[$this->db]]></code>
       <code><![CDATA[$this->db]]></code>
+      <code><![CDATA[$this->db]]></code>
+      <code><![CDATA[$this->db]]></code>
+      <code><![CDATA[$this->db]]></code>
+      <code><![CDATA[$this->db]]></code>
+      <code><![CDATA[$this->db]]></code>
+      <code><![CDATA[$this->db]]></code>
       <code><![CDATA[TransactionIsolationLevel]]></code>
       <code><![CDATA[\Doctrine\DBAL\ParameterType]]></code>
       <code><![CDATA[\Doctrine\DBAL\ParameterType]]></code>
@@ -191,6 +193,11 @@
       <code><![CDATA[\Doctrine\DBAL\Platforms\PostgreSQLPlatform]]></code>
       <code><![CDATA[\Doctrine\DBAL\Platforms\PostgreSQLPlatform]]></code>
       <code><![CDATA[\Doctrine\DBAL\Platforms\PostgreSQLPlatform]]></code>
+      <code><![CDATA[\Doctrine\DBAL\Platforms\PostgreSQLPlatform]]></code>
+      <code><![CDATA[\Doctrine\DBAL\Schema\ForeignKeyConstraint]]></code>
+      <code><![CDATA[\Doctrine\DBAL\Schema\Table]]></code>
+      <code><![CDATA[\Doctrine\DBAL\Schema\Table]]></code>
+      <code><![CDATA[\Doctrine\DBAL\Schema\Table]]></code>
       <code><![CDATA[\Doctrine\DBAL\Schema\Table]]></code>
       <code><![CDATA[\Doctrine\DBAL\Schema\Table]]></code>
       <code><![CDATA[\Doctrine\DBAL\Schema\Table]]></code>
@@ -213,21 +220,11 @@
     </PropertyNotSetInConstructor>
   </file>
   <file src="lib/Job/BackupRun.php">
-    <ArgumentTypeCoercion>
-      <code><![CDATA[$blobs]]></code>
-    </ArgumentTypeCoercion>
     <MissingParamType>
       <code><![CDATA[$fh]]></code>
     </MissingParamType>
-    <PossiblyNullIterator>
-      <code><![CDATA[$segments]]></code>
-    </PossiblyNullIterator>
     <PossiblyUndefinedArrayOffset>
       <code><![CDATA[$mtime]]></code>
-      <code><![CDATA[$state['cur']]]></code>
-      <code><![CDATA[$state['phase']]]></code>
-      <code><![CDATA[$state['segments']]]></code>
-      <code><![CDATA[$state['stats']]]></code>
     </PossiblyUndefinedArrayOffset>
   </file>
   <file src="lib/Job/ParentCursor.php">
@@ -395,7 +392,7 @@
   </file>
   <file src="lib/Service/BackupService.php">
     <InvalidOperand>
-      <code><![CDATA[$deadline - microtime(true) + 120]]></code>
+      <code><![CDATA[$deadline - microtime(true) + 600]]></code>
     </InvalidOperand>
     <UndefinedClass>
       <code><![CDATA[\OC]]></code>
@@ -409,24 +406,6 @@
     <ArgumentTypeCoercion>
       <code><![CDATA[array_diff(range(1, self::MAX_SLOTS), $used)]]></code>
     </ArgumentTypeCoercion>
-    <InvalidReturnStatement>
-      <code><![CDATA[[
-			'version' => 1,
-			'app' => 'NG Backup',
-			'fingerprint' => $this->fingerprint(),
-			'kit_version' => $this->kitVersion(),
-			'confirmation_code' => $this->kitCode(),
-			'created' => gmdate('c'),
-			'wrapped_key' => $this->wrappedKey(),
-			'slots' => $this->slots(),
-			'instructions' => 'Keep this file safe, outside this server. Any one of the passphrases of the slots listed here opens it. '
-				. 'To restore on a new server: install NG Backup, add the backup location and enter this kit with one passphrase. '
-				. 'Without the kit (or the location) and a passphrase, the backups cannot be decrypted.',
-		]]]></code>
-    </InvalidReturnStatement>
-    <InvalidReturnType>
-      <code><![CDATA[array{version:int, app:string, fingerprint:string, created:string, wrapped_key:array, instructions:string}]]></code>
-    </InvalidReturnType>
     <LessSpecificReturnStatement>
       <code><![CDATA[array_map(fn ($s) => ['slot' => $s['slot'], 'label' => $s['label'], 'created' => $s['created']], $this->wrappedKey()['slots'])]]></code>
     </LessSpecificReturnStatement>
@@ -455,6 +434,18 @@
       <code><![CDATA[array{kept: array<string, list<string>>, forgotten: list<string>, purged: list<string>, prune: array}]]></code>
     </MoreSpecificReturnType>
   </file>
+  <file src="lib/Service/RestoreFullService.php">
+    <EmptyArrayAccess>
+      <code><![CDATA[$backupConfig[$key]]]></code>
+    </EmptyArrayAccess>
+    <UndefinedInterfaceMethod>
+      <code><![CDATA[getInner]]></code>
+      <code><![CDATA[getInner]]></code>
+    </UndefinedInterfaceMethod>
+    <UnresolvableInclude>
+      <code><![CDATA[include $path]]></code>
+    </UnresolvableInclude>
+  </file>
   <file src="lib/Service/RestoreService.php">
     <LessSpecificReturnStatement>
       <code><![CDATA[array_values($children)]]></code>
@@ -481,12 +472,6 @@
     </RedundantCastGivenDocblockType>
   </file>
   <file src="lib/Service/TargetService.php">
-    <InvalidReturnStatement>
-      <code><![CDATA[$this->factory()->describeBackends()]]></code>
-    </InvalidReturnStatement>
-    <InvalidReturnType>
-      <code><![CDATA[list<array{id:string, name:string, auth:list<string>, parameters:array}>]]></code>
-    </InvalidReturnType>
     <UndefinedDocblockClass>
       <code><![CDATA[Server::get(\OCA\Files_External\Service\BackendService::class)]]></code>
     </UndefinedDocblockClass>

psalm.xml

@@ -31,8 +31,17 @@
             <errorLevel type="suppress">
                 <!-- Provided by files_external at runtime; not a composer dependency (PLAN.md 3.5). -->
                 <referencedClass name="OCA\Files_External\**" />
+                <!-- Provided by user_migration at runtime, an optional dependency (PLAN.md 3.8). -->
+                <referencedClass name="OCA\UserMigration\**" />
             </errorLevel>
         </UndefinedClass>
+        <UndefinedDocblockClass>
+            <errorLevel type="suppress">
+                <!-- Server::get()'s templated return type resolving the users_migration class-string
+                     constant below; same reason as the UndefinedClass suppression above. -->
+                <referencedClass name="OCA\UserMigration\**" />
+            </errorLevel>
+        </UndefinedDocblockClass>
         <!-- The #[\Override] attribute convention (PHP 8.3+) adds no behaviour; this app supports
              PHP 8.1+, and applying it to every interface-implementing method project-wide is pure
              ceremony with no bug-catching value, so it's suppressed rather than papered over. -->

src/AdminSettings.vue

@@ -6,23 +6,48 @@
 	<div class="ng-backup">
 		<NcSettingsSection :name="t('ng_backup', 'NG Backup')"
 			:description="t('ng_backup', 'Encrypted, incremental backups of this Nextcloud (database, configuration and data). Backup locations are never mounted and are not visible in Files.')">
+			<p class="ngb-feedback">
+				{{ t('ng_backup', 'We would like to hear how NG Backup works for you, also when everything went fine.') }}
+				<a :href="feedbackUrl" target="_blank" rel="noopener noreferrer">{{ t('ng_backup', 'Share your experience ↗') }}</a>
+			</p>
 			<NcLoadingIcon v-if="!status" :size="32" />
 			<NcNoteCard v-if="error" type="error">{{ error }}</NcNoteCard>
+			<NcNoteCard v-if="status && !status.cron.ok" type="warning">
+				<p>
+					{{ status.cron.stopped
+						? t('ng_backup', 'Background jobs are set to system cron, but cron has not run since {time}.', { time: lastCron })
+						: t('ng_backup', 'Background jobs do not run on a system cron (they are set to "{mode}").', { mode: status.cron.mode === 'webcron' ? 'Webcron' : 'AJAX' }) }}
+					{{ t('ng_backup', 'Backups need a system cron that runs every 5 minutes, also the scheduled ones.') }}
+					<a :href="status.cron.docs" target="_blank" rel="noopener noreferrer">{{ t('ng_backup', 'How to set up cron ↗') }}</a>
+				</p>
+				<p>{{ t('ng_backup', 'Until then, a backup started with "Back up now" only moves on while this page is open.') }}</p>
+			</NcNoteCard>
 		</NcSettingsSection>
 
 		<template v-if="status">
 			<div class="ngb-tabs">
 				<NcButton :variant="tab === 'backup' ? 'primary' : 'secondary'" @click="tab = 'backup'">{{ t('ng_backup', 'Backup and restore') }}</NcButton>
+				<NcButton v-if="status.key.everConfirmed && status.targets.length" :variant="tab === 'bin' ? 'primary' : 'secondary'" @click="tab = 'bin'">{{ t('ng_backup', 'Bin') }}</NcButton>
 				<NcButton :variant="tab === 'settings' ? 'primary' : 'secondary'" @click="tab = 'settings'">{{ t('ng_backup', 'Settings') }}</NcButton>
+				<NcButton :variant="tab === 'docs' ? 'primary' : 'secondary'" @click="tab = 'docs'">{{ t('ng_backup', 'Docs') }}</NcButton>
 			</div>
 
-			<template v-if="tab === 'settings'">
+			<NcSettingsSection v-if="tab === 'docs'" :name="t('ng_backup', 'Documentation')">
+				<ul class="ngb-docs">
+					<li v-for="doc in docs" :key="doc.url">
+						<a :href="doc.url" target="_blank" rel="noopener noreferrer">{{ doc.name }} ↗</a>
+						<span>{{ doc.description }}</span>
+					</li>
+				</ul>
+			</NcSettingsSection>
+			<Bin v-else-if="tab === 'bin' && status.key.everConfirmed && status.targets.length" :status="status" @changed="refresh" />
+			<template v-else-if="tab === 'settings'">
 				<KeySetup :status="status" @changed="refresh" />
 				<Locations v-if="status.key.everConfirmed" :status="status" @changed="refresh" />
 			</template>
 			<template v-else-if="status.key.everConfirmed">
 				<template v-if="status.targets.length">
-					<Backups :status="status" @changed="refresh" />
+					<Backups :status="status" :all-runs="allRuns" @changed="refresh" @show-all-runs="showAllRuns" />
 					<RestoreBrowser :status="status" @changed="refresh" />
 				</template>
 				<NcNoteCard v-else type="info">{{ t('ng_backup', 'Add a backup location under "Settings" first.') }}</NcNoteCard>
@@ -33,7 +58,7 @@
 </template>
 
 <script setup>
-import { onBeforeUnmount, onMounted, ref } from 'vue'
+import { computed, onBeforeUnmount, onMounted, ref } from 'vue'
 import { t } from '@nextcloud/l10n'
 import NcButton from '@nextcloud/vue/components/NcButton'
 import NcLoadingIcon from '@nextcloud/vue/components/NcLoadingIcon'
@@ -41,19 +66,48 @@ import NcNoteCard from '@nextcloud/vue/components/NcNoteCard'
 import NcSettingsSection from '@nextcloud/vue/components/NcSettingsSection'
 import api from './api.js'
 import Backups from './components/Backups.vue'
+import Bin from './components/Bin.vue'
 import KeySetup from './components/KeySetup.vue'
 import Locations from './components/Locations.vue'
 import RestoreBrowser from './components/RestoreBrowser.vue'
 
+// Opens the experience report form in .github/ISSUE_TEMPLATE
+const feedbackUrl = 'https://github.com/dillardblom/ng_backup/issues/new?template=experience.yml'
+
+const repoUrl = 'https://github.com/dillardblom/ng_backup'
+const docs = [
+	{
+		name: t('ng_backup', 'How-to'),
+		description: t('ng_backup', 'Step by step: from first install to a tested restore.'),
+		url: repoUrl + '/blob/main/docs/HOWTO.md',
+	},
+	{
+		name: t('ng_backup', 'Disaster recovery'),
+		description: t('ng_backup', 'Your server is gone: get Nextcloud back on a new server from a backup location.'),
+		url: repoUrl + '/blob/main/docs/DISASTER-RECOVERY.md',
+	},
+	{
+		name: t('ng_backup', 'Roadmap'),
+		description: t('ng_backup', 'What is planned for the next versions.'),
+		url: repoUrl + '#roadmap',
+	},
+]
+
 const status = ref(null)
+const allRuns = ref(false) // runs older than the last days too
 const error = ref('')
 const tab = ref('settings')
 let tabInitialized = false
 let timer = null
 
+function showAllRuns(all) {
+	allRuns.value = all
+	refresh()
+}
+
 async function refresh() {
 	try {
-		status.value = await api.status()
+		status.value = await api.status(allRuns.value)
 		error.value = ''
 		// Default to the daily-use tab once the key is set up; stay on Settings otherwise.
 		// Only decided on first load, so switching tabs ourselves isn't undone by polling.
@@ -64,24 +118,60 @@ async function refresh() {
 	} catch (e) {
 		error.value = e.message
 	}
-	// Poll while something runs, so progress shows up without reloading.
+	// Poll while something runs, so progress shows up without reloading. Without a working
+	// system cron, each poll also lets a running backup take a short step (see tick()).
 	clearTimeout(timer)
 	if (status.value?.runs.some(r => r.status === 'running')) {
-		timer = setTimeout(refresh, 4000)
+		timer = setTimeout(tickAndRefresh, 4000)
 	}
 }
 
+async function tickAndRefresh() {
+	if (status.value && !status.value.cron.ok && status.value.runs.some(r => r.status === 'running' && r.kind === 'full')) {
+		try {
+			await api.tick()
+		} catch (e) {
+			// The next poll tries again; the error of a failed step shows on its run.
+		}
+	}
+	await refresh()
+}
+
+const lastCron = computed(() => status.value?.cron.lastRun ? new Date(status.value.cron.lastRun * 1000).toLocaleString() : '')
+
 onMounted(refresh)
 onBeforeUnmount(() => clearTimeout(timer))
 </script>
 
 <style scoped>
+/* NcSettingsSection sets its own width (at most 900px): the runs table needs more */
 .ng-backup :deep(.settings-section) {
-	max-width: 900px;
+	width: min(1400px, 100% - var(--default-grid-baseline) * 7 * 2);
+	max-width: none;
+}
+.ngb-feedback {
+	color: var(--color-text-maxcontrast);
+	margin-bottom: 12px;
+}
+.ngb-feedback a {
+	color: var(--color-primary-element);
+	text-decoration: underline;
+}
+.ngb-docs li {
+	margin-bottom: 8px;
+}
+.ngb-docs a {
+	color: var(--color-primary-element);
+	text-decoration: underline;
+	margin-right: 8px;
+}
+.ngb-docs span {
+	color: var(--color-text-maxcontrast);
 }
 .ngb-tabs {
 	display: flex;
 	gap: 8px;
-	margin: 0 0 12px;
+	/* Same inline margin as NcSettingsSection, so the tabs line up with the section content */
+	margin: 0 calc(var(--default-grid-baseline) * 7) 12px;
 }
 </style>

src/api.js

@@ -16,7 +16,7 @@ async function call(method, path, data) {
 }
 
 export default {
-	status: () => call('get', '/status'),
+	status: (allRuns = false) => call('get', '/status', allRuns ? { allRuns: true } : undefined),
 	initKey: (passphrase, deleteDelayDays, label) => call('post', '/key', { passphrase, deleteDelayDays, label }),
 	addSlot: (passphrase, label) => call('post', '/key/slots', { passphrase, label }),
 	replaceSlot: (slot, passphrase, label) => call('put', `/key/slots/${slot}`, { passphrase, label }),
@@ -27,11 +27,14 @@ export default {
 	confirmKit: (accepted, phrase, code) => call('post', '/key/confirm', { accepted, phrase, code }),
 	backends: () => call('get', '/backends'),
 	addTarget: (target) => call('post', '/targets', target),
+	targetSettings: (id) => call('get', `/targets/${id}/settings`),
+	updateTarget: (id, target) => call('put', `/targets/${id}`, target),
 	removeTarget: (id) => call('delete', `/targets/${id}`),
 	testTarget: (id) => call('post', `/targets/${id}/test`),
 	setTargetLimit: (id, maxGb) => call('put', `/targets/${id}/limit`, { maxGb }),
 	startBackup: (targetId, label) => call('post', '/backups', { targetId, label }),
-	setSchedule: (time) => call('put', '/schedule', { time }),
+	tick: () => call('post', '/tick'),
+	setSchedule: (time, timezone) => call('put', '/schedule', { time, timezone }),
 	snapshots: (targetId) => call('get', `/targets/${targetId}/snapshots`),
 	browse: (targetId, snapshotId, path) => call('get', `/targets/${targetId}/snapshots/${snapshotId}/browse`, { path }),
 	startRestore: (targetId, snapshotId, path, mode) => call('post', '/restores', { targetId, snapshotId, path, mode }),

src/components/Backups.vue

@@ -6,106 +6,111 @@
 	<NcSettingsSection :name="t('ng_backup', 'Backups')"
 		:description="t('ng_backup', 'Backups run in the background through Nextcloud\'s cron. Unchanged files are not read again; only new data is uploaded.')">
 		<div class="ngb-row">
-			<NcTextField v-model="schedule" class="ngb-time" :label="t('ng_backup', 'Daily at (HH:MM, empty = off)')" />
-			<NcButton :disabled="schedule === status.schedule" @click="saveSchedule">{{ t('ng_backup', 'Save') }}</NcButton>
+			<NcTextField v-model="schedule" class="ngb-time" :label="t('ng_backup', 'Daily at (HH:MM, {zone}, empty = off)', { zone: browserZone })" />
+			<NcButton :disabled="schedule === status.schedule && browserZone === status.scheduleTimezone" @click="saveSchedule">{{ t('ng_backup', 'Save') }}</NcButton>
 		</div>
 		<div class="ngb-row">
+			<NcTextField v-model="label" class="ngb-label" :maxlength="100" :label="t('ng_backup', 'Label (optional)')"
+				:placeholder="t('ng_backup', 'e.g. before the upgrade to Nextcloud 35')" />
 			<NcButton v-for="target in status.targets" :key="target.id" :disabled="isRunning(target.id)" @click="start(target)">
 				{{ isRunning(target.id) ? t('ng_backup', 'Backup to {name} running …', { name: target.name }) : t('ng_backup', 'Back up now to {name}', { name: target.name }) }}
 			</NcButton>
 		</div>
 		<NcNoteCard v-if="error" type="error">{{ error }}</NcNoteCard>
 
-		<template v-for="target in status.targets" :key="'trash' + target.id">
-			<div v-if="trash[target.id]?.length" class="ngb-trash">
-				<h3>{{ t('ng_backup', 'Trash of {name}', { name: target.name }) }}</h3>
-				<p class="ngb-muted">{{ t('ng_backup', 'Removed restore points can be brought back until they are deleted permanently.') }}</p>
-				<ul>
-					<li v-for="item in trash[target.id]" :key="item.id">
-						{{ item.time ? new Date(item.time).toLocaleString() : item.id }}{{ item.label ? ' – ' + item.label : '' }}
-						<span class="ngb-muted">{{ t('ng_backup', 'removed by {by}, deleted after {date}', { by: item.by, date: new Date(item.deleteAfter * 1000).toLocaleDateString() }) }}</span>
-						<NcButton variant="tertiary" @click="untrash(target, item)">{{ t('ng_backup', 'Restore') }}</NcButton>
-					</li>
-				</ul>
-			</div>
-		</template>
-
-		<table v-if="status.runs.length" class="ngb-table">
-			<thead>
-				<tr>
-					<th>{{ t('ng_backup', 'Started') }}</th>
-					<th>{{ t('ng_backup', 'Location') }}</th>
-					<th>{{ t('ng_backup', 'Kind') }}</th>
-					<th>{{ t('ng_backup', 'Restore point') }}</th>
-					<th>{{ t('ng_backup', 'Status') }}</th>
-					<th>{{ t('ng_backup', 'Files') }}</th>
-					<th>{{ t('ng_backup', 'Uploaded') }}</th>
-				</tr>
-			</thead>
-			<tbody>
-				<tr v-for="run in status.runs" :key="run.id" :title="run.error || ''">
-					<td>{{ new Date(run.startedAt * 1000).toLocaleString() }}</td>
-					<td>{{ targetName(run.targetId) }}</td>
-					<td>{{ run.kind }}</td>
-					<td>{{ run.snapshot ? new Date(run.snapshot.createdAt * 1000).toLocaleString() + (run.snapshot.label ? ' – ' + run.snapshot.label : '') : '' }}</td>
-					<td :class="'ngb-' + run.status">{{ run.status }}{{ run.status === 'running' ? ' (' + run.phase + ')' : '' }}{{ run.error ? ': ' + run.error : '' }}</td>
-					<td>{{ run.stats?.files?.files ?? run.stats?.restored ?? '' }}</td>
-					<td>{{ run.stats?.files ? formatSize(run.stats.files.uploaded) : '' }}</td>
-				</tr>
-			</tbody>
-		</table>
+		<div v-if="status.runs.length" class="ngb-table-wrap">
+			<table class="ngb-table">
+				<thead>
+					<tr>
+						<th>{{ t('ng_backup', 'Started') }}</th>
+						<th>{{ t('ng_backup', 'Location') }}</th>
+						<th>{{ t('ng_backup', 'Kind') }}</th>
+						<th>{{ t('ng_backup', 'Restore point') }}</th>
+						<th>{{ t('ng_backup', 'Status') }}</th>
+						<th>{{ t('ng_backup', 'Files') }}</th>
+						<th :title="t('ng_backup', 'Total size of the files in this backup, unchanged files included')">{{ t('ng_backup', 'Size') }}</th>
+						<th>{{ t('ng_backup', 'Uploaded') }}</th>
+					</tr>
+				</thead>
+				<tbody>
+					<tr v-for="run in status.runs" :key="run.id" :title="run.error || ''">
+						<td>{{ formatDateTime(run.startedAt) }}</td>
+						<td>{{ targetName(run.targetId) }}</td>
+						<td>{{ run.kind }}</td>
+						<td>{{ run.snapshot ? formatDateTime(run.snapshot.createdAt) + (run.snapshot.label ? ' – ' + run.snapshot.label : '') : '' }}</td>
+						<td :class="'ngb-' + run.status">{{ runStatus(run) }}{{ run.error ? ': ' + run.error : '' }}</td>
+						<td>{{ run.stats?.files?.files ?? run.stats?.restored ?? '' }}</td>
+						<td>{{ run.stats?.files ? formatSize(run.stats.files.bytes) : '' }}</td>
+						<td>{{ run.stats?.files ? formatSize(run.stats.files.uploaded) : '' }}</td>
+					</tr>
+				</tbody>
+			</table>
+		</div>
+		<p v-if="allRuns || status.olderRuns" class="ngb-muted">
+			<template v-if="allRuns">
+				{{ t('ng_backup', 'All runs.') }}
+				<NcButton variant="tertiary" @click="emit('show-all-runs', false)">{{ n('ng_backup', 'Only the last day', 'Only the last %n days', status.recentDays) }}</NcButton>
+			</template>
+			<template v-else>
+				{{ n('ng_backup', 'Runs of the last day.', 'Runs of the last %n days.', status.recentDays) }}
+				<NcButton variant="tertiary" @click="emit('show-all-runs', true)">{{ n('ng_backup', 'Show %n older run', 'Show %n older runs', status.olderRuns) }}</NcButton>
+			</template>
+		</p>
 	</NcSettingsSection>
 </template>
 
 <script setup>
 import { ref, watch } from 'vue'
-import { t } from '@nextcloud/l10n'
+import { n, t } from '@nextcloud/l10n'
 import NcButton from '@nextcloud/vue/components/NcButton'
 import NcNoteCard from '@nextcloud/vue/components/NcNoteCard'
 import NcSettingsSection from '@nextcloud/vue/components/NcSettingsSection'
 import NcTextField from '@nextcloud/vue/components/NcTextField'
 import api from '../api.js'
-import { formatSize } from '../format.js'
-import { confirmPassword } from '@nextcloud/password-confirmation'
-import { reactive } from 'vue'
+import { formatDateTime, formatSize, toZone } from '../format.js'
 
-const props = defineProps({ status: { type: Object, required: true } })
-const emit = defineEmits(['changed'])
-const schedule = ref(props.status.schedule)
+const props = defineProps({ status: { type: Object, required: true }, allRuns: { type: Boolean, default: false } })
+const emit = defineEmits(['changed', 'show-all-runs'])
+// The time is saved in the administrator's own zone (the browser's); a schedule saved in another
+// zone is shown in this one, so it reads as the moment it runs here.
+const browserZone = Intl.DateTimeFormat().resolvedOptions().timeZone || 'UTC'
+const shown = (s) => (s && props.status.scheduleTimezone && props.status.scheduleTimezone !== browserZone) ? toZone(s, props.status.scheduleTimezone, browserZone) : s
+const schedule = ref(shown(props.status.schedule))
 const error = ref('')
-watch(() => props.status.schedule, (s) => { schedule.value = s })
+watch(() => [props.status.schedule, props.status.scheduleTimezone], ([s]) => { schedule.value = shown(s) })
 
-const trash = reactive({})
-async function loadTrash() {
-	for (const target of props.status.targets) {
-		try {
-			trash[target.id] = await api.trash(target.id)
-		} catch (e) {
-			trash[target.id] = []
-		}
+const label = ref('')
+
+// ": 47/183 tables" in the database phase; " 68%", or " ~68%" when the total is estimated from
+// Nextcloud's file cache (first backup)
+const percent = (run) => {
+	if (!run.progress) {
+		return ''
 	}
-}
-watch(() => props.status.targets.map(tg => tg.id).join(','), loadTrash, { immediate: true })
-
-async function untrash(target, item) {
-	error.value = ''
-	try {
-		await confirmPassword()
-		await api.untrash(target.id, item.id)
-		await loadTrash()
-		emit('changed')
-	} catch (e) {
-		error.value = e?.message || ''
+	if (run.progress.totalTables) {
+		return ': ' + t('ng_backup', '{done}/{total} tables', { done: run.progress.tables, total: run.progress.totalTables })
 	}
+	return ' ' + (run.progress.approximate ? '~' : '') + Math.floor(run.progress.fraction * 100) + '%'
+}
+// "running (db: 47/183 tables)", or "waiting for background jobs (…, last step 12 min ago)"
+const runStatus = (run) => {
+	if (run.status !== 'running') {
+		return run.status
+	}
+	const detail = run.phase + percent(run)
+	if (run.waitingFor) {
+		return t('ng_backup', 'waiting for background jobs ({detail}, last step {minutes} min ago)', { detail, minutes: Math.floor(run.waitingFor / 60) })
+	}
+	return run.status + ' (' + detail + ')'
 }
-
 const isRunning = (targetId) => props.status.runs.some(r => r.targetId === targetId && r.kind === 'full' && r.status === 'running')
 const targetName = (id) => props.status.targets.find(tg => tg.id === id)?.name ?? '#' + id
 
 async function start(target) {
 	error.value = ''
 	try {
-		await api.startBackup(target.id, '')
+		await api.startBackup(target.id, label.value.trim())
+		label.value = ''
 		emit('changed')
 	} catch (e) {
 		error.value = e.message
@@ -115,7 +120,7 @@ async function start(target) {
 async function saveSchedule() {
 	error.value = ''
 	try {
-		await api.setSchedule(schedule.value.trim())
+		await api.setSchedule(schedule.value.trim(), browserZone)
 		emit('changed')
 	} catch (e) {
 		error.value = e.message
@@ -126,11 +131,11 @@ async function saveSchedule() {
 <style scoped>
 .ngb-row { display: flex; gap: 8px; align-items: flex-end; flex-wrap: wrap; margin-bottom: 12px; }
 .ngb-time { max-width: 260px; }
+.ngb-label { max-width: 360px; }
+.ngb-table-wrap { overflow-x: auto; }
 .ngb-table { width: 100%; border-collapse: collapse; }
 .ngb-table th, .ngb-table td { text-align: start; padding: 4px 8px; border-bottom: 1px solid var(--color-border); }
 .ngb-failed { color: var(--color-error-text); }
 .ngb-muted { color: var(--color-text-maxcontrast); }
-.ngb-trash { margin: 12px 0; }
-.ngb-trash h3 { font-weight: bold; }
 .ngb-done { color: var(--color-success-text); }
 </style>

src/components/Bin.vue

@@ -0,0 +1,93 @@
+<!--
+  - SPDX-FileCopyrightText: 2026 Dillard Blom
+  - SPDX-License-Identifier: AGPL-3.0-or-later
+-->
+<template>
+	<NcSettingsSection :name="t('ng_backup', 'Bin')"
+		:description="t('ng_backup', 'Restore points that were removed, most of them by the retention policy. They can be brought back until they are deleted permanently.')">
+		<NcNoteCard v-if="error" type="error">{{ error }}</NcNoteCard>
+		<NcLoadingIcon v-if="loading" :size="32" />
+		<NcNoteCard v-else-if="empty" type="info">{{ t('ng_backup', 'The bin is empty.') }}</NcNoteCard>
+
+		<template v-for="target in status.targets" :key="'trash' + target.id">
+			<div v-if="trash[target.id]?.length" class="ngb-trash">
+				<h3>{{ status.targets.length > 1 ? target.name : t('ng_backup', 'Removed restore points') }}</h3>
+				<ul>
+					<li v-for="item in trash[target.id]" :key="item.id">
+						{{ item.time ? formatDateTime(item.time) : item.id }}{{ item.label ? ' – ' + item.label : '' }}
+						<span class="ngb-muted">{{ t('ng_backup', 'removed by {by}, deleted after {date}', { by: item.by, date: formatDate(item.deleteAfter) }) }}</span>
+						<button v-if="item.by === RETENTION"
+							class="ngb-info"
+							:aria-expanded="retentionInfo ? 'true' : 'false'"
+							:aria-label="t('ng_backup', 'What does this mean?')"
+							:title="t('ng_backup', 'What does this mean?')"
+							@click="retentionInfo = !retentionInfo">
+							ⓘ
+						</button>
+						<NcButton variant="tertiary" @click="untrash(target, item)">{{ t('ng_backup', 'Restore') }}</NcButton>
+					</li>
+				</ul>
+				<NcNoteCard v-if="retentionInfo && trash[target.id].some(item => item.by === RETENTION)" type="info">
+					{{ n('ng_backup',
+						'The retention policy keeps the newest restore points, and for older days, weeks and months only the last restore point of each. It moves the others to this bin, where they stay for %n day before they are deleted permanently. Until then you can bring one back with "Restore". Nothing was lost by accident.',
+						'The retention policy keeps the newest restore points, and for older days, weeks and months only the last restore point of each. It moves the others to this bin, where they stay for %n days before they are deleted permanently. Until then you can bring one back with "Restore". Nothing was lost by accident.',
+						status.key.deleteDelayDays) }}
+				</NcNoteCard>
+			</div>
+		</template>
+	</NcSettingsSection>
+</template>
+
+<script setup>
+import { computed, reactive, ref, watch } from 'vue'
+import { n, t } from '@nextcloud/l10n'
+import { confirmPassword } from '@nextcloud/password-confirmation'
+import NcButton from '@nextcloud/vue/components/NcButton'
+import NcLoadingIcon from '@nextcloud/vue/components/NcLoadingIcon'
+import NcNoteCard from '@nextcloud/vue/components/NcNoteCard'
+import NcSettingsSection from '@nextcloud/vue/components/NcSettingsSection'
+import api from '../api.js'
+import { formatDate, formatDateTime } from '../format.js'
+
+const props = defineProps({ status: { type: Object, required: true } })
+const emit = defineEmits(['changed'])
+
+// "by" of a restore point the weekly cleanup removed (PruneService)
+const RETENTION = 'retention policy'
+const retentionInfo = ref(false)
+const trash = reactive({})
+const loading = ref(true)
+const error = ref('')
+const empty = computed(() => props.status.targets.every(target => !trash[target.id]?.length))
+
+async function loadTrash() {
+	for (const target of props.status.targets) {
+		try {
+			trash[target.id] = await api.trash(target.id)
+		} catch (e) {
+			trash[target.id] = []
+		}
+	}
+	loading.value = false
+}
+watch(() => props.status.targets.map(tg => tg.id).join(','), loadTrash, { immediate: true })
+
+async function untrash(target, item) {
+	error.value = ''
+	try {
+		await confirmPassword()
+		await api.untrash(target.id, item.id)
+		await loadTrash()
+		emit('changed')
+	} catch (e) {
+		error.value = e?.message || ''
+	}
+}
+</script>
+
+<style scoped>
+.ngb-info { background: none; border: none; padding: 0 4px; min-height: auto; cursor: pointer; color: var(--color-primary-element); }
+.ngb-muted { color: var(--color-text-maxcontrast); }
+.ngb-trash { margin: 12px 0; }
+.ngb-trash h3 { font-weight: bold; }
+</style>

src/components/KeySetup.vue

@@ -8,13 +8,13 @@
 		<!-- 1. Create the key -->
 		<form v-if="!status.key.initialized" class="ngb-form" @submit.prevent="createKey">
 			<NcTextField v-model="label" :label="t('ng_backup', 'Who keeps this passphrase (e.g. Safe, CTO)')" />
-			<NcPasswordField v-model="pass1" :label="t('ng_backup', 'Passphrase (at least 12 characters)')" autocomplete="new-password" />
+			<NcPasswordField v-model="pass1" :label="t('ng_backup', 'Passphrase (at least 16 characters)')" autocomplete="new-password" />
 			<NcPasswordField v-model="pass2" :label="t('ng_backup', 'Repeat passphrase')" autocomplete="new-password"
 				:error="pass2 !== '' && pass1 !== pass2" :helper-text="pass2 !== '' && pass1 !== pass2 ? t('ng_backup', 'The passphrases do not match') : ''" />
 			<NcTextField v-model="delay" type="number" min="1" max="365"
-				:label="t('ng_backup', 'Days a removed backup stays in the trash before it is really deleted')"
+				:label="t('ng_backup', 'Days a removed backup stays in the Bin before it is really deleted')"
 				:helper-text="t('ng_backup', 'Protects against a malicious or mistaken cleanup. Cannot be changed later.')" />
-			<NcButton type="submit" variant="primary" :disabled="busy || pass1.length < 12 || pass1 !== pass2 || !(delay >= 1 && delay <= 365)">
+			<NcButton type="submit" variant="primary" :disabled="busy || pass1.length < 16 || pass1 !== pass2 || !(delay >= 1 && delay <= 365)">
 				{{ t('ng_backup', 'Create backup key') }}
 			</NcButton>
 		</form>
@@ -22,7 +22,7 @@
 		<template v-else>
 			<p>
 				{{ t('ng_backup', 'Key fingerprint: {fingerprint}', { fingerprint: status.key.fingerprint }) }} ·
-				{{ t('ng_backup', 'Removed backups are kept in the trash for {days} days', { days: status.key.deleteDelayDays }) }}
+				{{ t('ng_backup', 'Removed backups are kept in the Bin for {days} days', { days: status.key.deleteDelayDays }) }}
 			</p>
 
 			<!-- Passphrase slots -->
@@ -35,8 +35,8 @@
 					<tr v-for="slot in status.key.slots" :key="slot.slot">
 						<td>{{ t('ng_backup', 'Slot {n}', { n: slot.slot }) }}</td>
 						<td><strong>{{ slot.label }}</strong></td>
-						<td class="ngb-muted">{{ slot.created ? new Date(slot.created * 1000).toLocaleDateString() : '' }}</td>
-						<td>
+						<td class="ngb-muted">{{ slot.created ? formatDate(slot.created) : '' }}</td>
+						<td class="ngb-actions">
 							<NcButton variant="tertiary" @click="openSlotForm(slot)">{{ t('ng_backup', 'New passphrase') }}</NcButton>
 							<NcButton v-if="status.key.slots.length > 1" variant="tertiary" @click="removeSlot(slot)">{{ t('ng_backup', 'Remove') }}</NcButton>
 						</td>
@@ -46,10 +46,10 @@
 			<NcButton v-if="!slotForm && status.key.slots.length < status.key.maxSlots" @click="openSlotForm(null)">{{ t('ng_backup', 'Add passphrase') }}</NcButton>
 			<form v-if="slotForm" class="ngb-form" @submit.prevent="saveSlot">
 				<NcTextField v-model="slotForm.label" :label="t('ng_backup', 'Who keeps this passphrase')" />
-				<NcPasswordField v-model="slotForm.pass1" :label="t('ng_backup', 'Passphrase (at least 12 characters)')" autocomplete="new-password" />
+				<NcPasswordField v-model="slotForm.pass1" :label="t('ng_backup', 'Passphrase (at least 16 characters)')" autocomplete="new-password" />
 				<NcPasswordField v-model="slotForm.pass2" :label="t('ng_backup', 'Repeat passphrase')" autocomplete="new-password" :error="slotForm.pass2 !== '' && slotForm.pass1 !== slotForm.pass2" />
 				<div class="ngb-row">
-					<NcButton type="submit" variant="primary" :disabled="busy || slotForm.pass1.length < 12 || slotForm.pass1 !== slotForm.pass2">{{ t('ng_backup', 'Save') }}</NcButton>
+					<NcButton type="submit" variant="primary" :disabled="busy || slotForm.pass1.length < 16 || slotForm.pass1 !== slotForm.pass2">{{ t('ng_backup', 'Save') }}</NcButton>
 					<NcButton @click="slotForm = null">{{ t('ng_backup', 'Cancel') }}</NcButton>
 				</div>
 			</form>
@@ -69,7 +69,7 @@
 				<NcButton variant="primary" :disabled="!downloaded || !accepted || code.length < 8 || busy" @click="confirm">{{ status.confirmationPhrase }}</NcButton>
 			</div>
 			<p v-else>
-				{{ t('ng_backup', 'Recovery kit confirmed by {user} on {date}.', { user: status.key.confirmation.uid, date: new Date(status.key.confirmation.time * 1000).toLocaleString() }) }}
+				{{ t('ng_backup', 'Recovery kit confirmed by {user} on {date}.', { user: status.key.confirmation.uid, date: formatDateTime(status.key.confirmation.time) }) }}
 				<NcButton variant="tertiary" @click="downloadKit">{{ t('ng_backup', 'Download the kit again') }}</NcButton>
 				<span class="ngb-muted">{{ t('ng_backup', 'Requires your password; all administrators are notified.') }}</span>
 			</p>
@@ -90,6 +90,7 @@ import NcPasswordField from '@nextcloud/vue/components/NcPasswordField'
 import NcSettingsSection from '@nextcloud/vue/components/NcSettingsSection'
 import NcTextField from '@nextcloud/vue/components/NcTextField'
 import api from '../api.js'
+import { formatDateTime, formatDate } from '../format.js'
 
 const props = defineProps({ status: { type: Object, required: true } })
 const emit = defineEmits(['changed'])
@@ -162,5 +163,6 @@ const confirm = () => guarded(async () => {
 .ngb-form, .ngb-confirm { display: flex; flex-direction: column; gap: 12px; max-width: 600px; margin: 8px 0; }
 .ngb-row { display: flex; gap: 8px; }
 .ngb-table td { padding: 2px 12px 2px 0; }
+.ngb-actions { display: flex; gap: 4px; }
 h3 { margin-top: 16px; font-weight: bold; }
 </style>

src/components/Locations.vue

@@ -14,12 +14,16 @@
 					{{ tests[target.id].ok ? t('ng_backup', 'OK, {n} snapshots', { n: tests[target.id].snapshots }) : tests[target.id].error }}
 				</span>
 				<NcButton variant="tertiary" @click="test(target)">{{ t('ng_backup', 'Test') }}</NcButton>
+				<NcButton variant="tertiary" @click="startEdit(target)">{{ t('ng_backup', 'Edit') }}</NcButton>
 				<NcButton variant="tertiary" @click="remove(target)">{{ t('ng_backup', 'Remove') }}</NcButton>
 			</li>
 		</ul>
 
-		<NcButton v-if="!adding" @click="startAdd">{{ t('ng_backup', 'Add location') }}</NcButton>
-		<form v-else class="ngb-form" @submit.prevent="add">
+		<NcButton v-if="!adding" @click="startAdd()">{{ t('ng_backup', 'Add location') }}</NcButton>
+		<form v-else class="ngb-form" @submit.prevent="save">
+			<NcNoteCard v-if="editing" type="info">
+				{{ t('ng_backup', 'Editing "{name}". The new settings must lead to the same repository, so its backups and history are kept. Leave a password field empty to keep the stored password.', { name: editing.name }) }}
+			</NcNoteCard>
 			<NcTextField v-model="form.name" :label="t('ng_backup', 'Name')" />
 			<NcSelect v-model="backend" :options="backends" label="name" :input-label="t('ng_backup', 'Type')" :clearable="false" />
 			<NcSelect v-if="backend" v-model="auth" :options="backend.auth" label="name" :input-label="t('ng_backup', 'Authentication')" :clearable="false" />
@@ -32,8 +36,8 @@
 			<NcTextField v-model="form.maxGb" type="number" min="0" :label="t('ng_backup', 'Maximum size in GiB')"
 				:helper-text="form.maxGb ? t('ng_backup', 'Backups stop at this size; administrators are warned at 80%.') : t('ng_backup', 'Empty = unlimited: everything stored is billed by your provider, and nothing stops a backup that keeps growing.')" />
 			<div class="ngb-row">
-				<NcButton type="submit" variant="primary" :disabled="busy || !form.name || !backend || !auth">{{ t('ng_backup', 'Connect and add') }}</NcButton>
-				<NcButton @click="adding = false">{{ t('ng_backup', 'Cancel') }}</NcButton>
+				<NcButton type="submit" variant="primary" :disabled="busy || !form.name || !backend || !auth">{{ editing ? t('ng_backup', 'Connect and save') : t('ng_backup', 'Connect and add') }}</NcButton>
+				<NcButton @click="adding = false; editing = null">{{ t('ng_backup', 'Cancel') }}</NcButton>
 			</div>
 		</form>
 		<NcNoteCard v-if="error" type="error">{{ error }}</NcNoteCard>
@@ -41,7 +45,7 @@
 </template>
 
 <script setup>
-import { computed, reactive, ref, watch } from 'vue'
+import { computed, nextTick, reactive, ref, watch } from 'vue'
 import { t } from '@nextcloud/l10n'
 import NcButton from '@nextcloud/vue/components/NcButton'
 import NcCheckboxRadioSwitch from '@nextcloud/vue/components/NcCheckboxRadioSwitch'
@@ -58,6 +62,7 @@ defineProps({ status: { type: Object, required: true } })
 const emit = defineEmits(['changed'])
 
 const adding = ref(false)
+const editing = ref(null) // the target being edited, or null while adding
 const busy = ref(false)
 const error = ref('')
 const backends = ref([])
@@ -83,34 +88,83 @@ const toFields = (params) => Object.entries(params || {})
 	.map(([key, p]) => ({ key, label: p.value, type: p.type, optional: !!(p.flags & 1) }))
 const fields = computed(() => [...toFields(backend.value?.parameters), ...toFields(auth.value?.parameters)])
 
+let prefilling = false
 watch(backend, (b) => {
+	if (prefilling) {
+		return
+	}
 	auth.value = b?.auth?.[0] ?? null
 	form.options = {}
 })
 
-async function startAdd() {
-	adding.value = true
-	error.value = ''
+async function loadBackends() {
 	if (!backends.value.length) {
-		try {
-			backends.value = await api.backends()
-		} catch (e) {
-			error.value = e.message
-		}
+		backends.value = await api.backends()
 	}
 }
 
-async function add() {
-	busy.value = true
+async function startAdd() {
+	error.value = ''
+	editing.value = null
+	Object.assign(form, { name: '', path: 'ng_backup', options: {}, maxGb: '' })
+	backend.value = null
+	adding.value = true
+	try {
+		await loadBackends()
+	} catch (e) {
+		error.value = e.message
+	}
+}
+
+async function startEdit(target) {
 	error.value = ''
 	try {
-		await api.addTarget({ name: form.name, backend: backend.value.id, auth: auth.value.id, options: form.options, path: form.path,
-			maxGb: form.maxGb === '' ? null : Number(form.maxGb) })
+		await confirmPassword()
+		await loadBackends()
+		const settings = await api.targetSettings(target.id)
+		prefilling = true
+		backend.value = backends.value.find((b) => b.id === settings.backend) ?? null
+		auth.value = backend.value?.auth.find((a) => a.id === settings.auth) ?? null
+		Object.assign(form, { name: settings.name, path: settings.path, options: Object.fromEntries(Object.entries(settings.options).map(([k, v]) => [k, v ?? ''])),
+			maxGb: target.maxBytes ? String(+(target.maxBytes / 1073741824).toFixed(2)) : '' })
+		await nextTick()
+		prefilling = false
+		editing.value = target
+		adding.value = true
+	} catch (e) {
+		prefilling = false
+		error.value = e?.message || ''
+	}
+}
+
+async function save() {
+	busy.value = true
+	error.value = ''
+	const maxGb = form.maxGb === '' ? null : Number(form.maxGb)
+	try {
+		await confirmPassword()
+		if (editing.value) {
+			// An empty password field sends null: the server keeps the stored password.
+			const options = { ...form.options }
+			for (const field of fields.value) {
+				if (field.type === 2 && !options[field.key]) {
+					options[field.key] = null
+				}
+			}
+			await api.updateTarget(editing.value.id, { name: form.name, backend: backend.value.id, auth: auth.value.id, options, path: form.path })
+			if (maxGb !== (editing.value.maxBytes ? Number((editing.value.maxBytes / 1073741824).toFixed(2)) : null)) {
+				await api.setTargetLimit(editing.value.id, maxGb)
+			}
+			delete tests[editing.value.id]
+		} else {
+			await api.addTarget({ name: form.name, backend: backend.value.id, auth: auth.value.id, options: form.options, path: form.path, maxGb })
+		}
 		adding.value = false
+		editing.value = null
 		Object.assign(form, { name: '', path: 'ng_backup', options: {}, maxGb: '' })
 		emit('changed')
 	} catch (e) {
-		error.value = e.message
+		error.value = e?.message || ''
 	} finally {
 		busy.value = false
 	}

src/components/RestoreBrowser.vue

@@ -7,7 +7,7 @@
 		:description="t('ng_backup', 'Pick a restore point and a user folder or file. Restores run in the background and go through Nextcloud, so overwritten files keep their old content as a version and removed files go to the trash.')">
 		<div class="ngb-row">
 			<NcSelect v-model="target" :options="status.targets" label="name" :input-label="t('ng_backup', 'Location')" :clearable="false" />
-			<NcSelect v-if="target" v-model="snapshot" :options="snapshots" label="displayLabel" :input-label="t('ng_backup', 'Restore point')" :clearable="false" />
+			<NcSelect v-if="target" v-model="snapshot" :options="snapshots" label="displayLabel" class="ngb-snapshot" :input-label="t('ng_backup', 'Restore point')" :clearable="false" />
 		</div>
 
 		<template v-if="snapshot">
@@ -52,7 +52,7 @@ import NcSettingsSection from '@nextcloud/vue/components/NcSettingsSection'
 import { confirmPassword } from '@nextcloud/password-confirmation'
 import '@nextcloud/password-confirmation/style.css'
 import api from '../api.js'
-import { formatSize } from '../format.js'
+import { formatDateTime, formatSize } from '../format.js'
 
 const props = defineProps({ status: { type: Object, required: true } })
 const emit = defineEmits(['changed'])
@@ -69,12 +69,12 @@ const busy = ref(false)
 const error = ref('')
 const message = ref('')
 const modes = [
-	{ id: 'new-folder', label: t('ng_backup', 'Into a new folder "Restored <date>" (nothing existing is changed)') },
+	{ id: 'new-folder', label: t('ng_backup', 'Into a new folder "Restored {date}" (nothing existing is changed)', { date: 'YYYY-MM-DD HH.MM' }) },
 	{ id: 'merge', label: t('ng_backup', 'Into the original place, overwrite (old content kept as a version)') },
 	{ id: 'replace', label: t('ng_backup', 'Into the original place, overwrite and move files that are not in the backup to the trash') },
 ]
 
-const snapshotLabel = (s) => new Date(s.createdAt * 1000).toLocaleString() + (s.label ? ' – ' + s.label : '')
+const snapshotLabel = (s) => formatDateTime(s.createdAt) + (s.label ? ' – ' + s.label : '')
 const join = (name) => path.value + '/' + name
 const restorable = (p) => /^data\/[^/]+\/files(\/.*)?$/.test(p)
 const crumbs = computed(() => {
@@ -124,6 +124,7 @@ async function restore() {
 
 <style scoped>
 .ngb-row { display: flex; gap: 12px; flex-wrap: wrap; margin-bottom: 12px; }
+.ngb-row :deep(.ngb-snapshot) { min-width: min(360px, 100%); }
 .ngb-crumbs { display: flex; align-items: center; flex-wrap: wrap; }
 .ngb-entries li { display: flex; align-items: center; gap: 12px; min-height: 36px; }
 .ngb-entries li.selected { background: var(--color-primary-element-light); border-radius: var(--border-radius); }

src/format.js

@@ -1,5 +1,18 @@
 // SPDX-FileCopyrightText: 2026 Dillard Blom
 // SPDX-License-Identifier: AGPL-3.0-or-later
+import { getCanonicalLocale } from '@nextcloud/l10n'
+
+// The locale of the user's Nextcloud settings (Personal info > Locale), not the browser's:
+// a browser set to English would otherwise show 4:00 PM to someone with a 24-hour locale.
+const locale = getCanonicalLocale()
+
+// A number is a unix timestamp in seconds, a string an ISO 8601 date (snapshot times).
+const toDate = (value) => typeof value === 'number' ? new Date(value * 1000) : new Date(value)
+
+export const formatDateTime = (value) => toDate(value).toLocaleString(locale)
+
+export const formatDate = (value) => toDate(value).toLocaleDateString(locale)
+
 export function formatSize(bytes) {
 	if (bytes === null || bytes === undefined) {
 		return ''
@@ -13,3 +26,30 @@ export function formatSize(bytes) {
 	}
 	return i === 0 ? `${b} B` : `${b.toFixed(1)} ${units[i]}`
 }
+
+/**
+ * A time of day "HH:MM" in zone `from`, as "HH:MM" in zone `to`, at today's offsets.
+ *
+ * @param {string} hhmm the time
+ * @param {string} from IANA zone it is in
+ * @param {string} to IANA zone to show it in
+ * @param {Date} now the day to convert on (today)
+ * @return {string}
+ */
+export function toZone(hhmm, from, to, now = new Date()) {
+	const [h, m] = hhmm.split(':').map(Number)
+	const parts = (zone, date) => Object.fromEntries(new Intl.DateTimeFormat('en-GB', {
+		timeZone: zone, hourCycle: 'h23', year: 'numeric', month: '2-digit', day: '2-digit', hour: '2-digit', minute: '2-digit',
+	}).formatToParts(date).map((p) => [p.type, p.value]))
+	const offsetAt = (at) => {
+		const seen = parts(from, new Date(at))
+		return Date.UTC(+seen.year, +seen.month - 1, +seen.day, +seen.hour, +seen.minute) - at
+	}
+	const today = parts(from, now)
+	const wall = Date.UTC(+today.year, +today.month - 1, +today.day, h, m)
+	// the offset at the wall time itself: on a day the clocks change it differs from the one at
+	// midnight, so it is looked up a second time at the moment found first
+	const at = wall - offsetAt(wall - offsetAt(wall))
+	const there = parts(to, new Date(at))
+	return `${there.hour}:${there.minute}`
+}

tests/Unit/Backend/ExternalStorageFactoryTest.php

@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\NgBackup\Tests\Unit\Backend;
+
+use OCA\NgBackup\Backend\ExternalStorageFactory;
+use PHPUnit\Framework\TestCase;
+
+/** ExternalStorageFactory::normalizePrivateKey(): keys that phpseclib 2 read, for phpseclib 3 (#24). */
+class ExternalStorageFactoryTest extends TestCase {
+	/** An OpenSSH-format key laid out as ssh-keygen writes it; the body is random, not a real key. */
+	private static function key(): string {
+		$body = base64_encode(random_bytes(1000));
+		return "-----BEGIN OPENSSH PRIVATE KEY-----\n" . chunk_split($body, 70, "\n") . "-----END OPENSSH PRIVATE KEY-----\n";
+	}
+
+	public function testRestoresLostLineBreaks(): void {
+		$key = self::key();
+		$this->assertSame($key, ExternalStorageFactory::normalizePrivateKey($key));
+		$this->assertSame($key, ExternalStorageFactory::normalizePrivateKey(str_replace("\n", ' ', $key)), 'newlines as spaces');
+		$this->assertSame($key, ExternalStorageFactory::normalizePrivateKey(str_replace("\n", '', $key)), 'no newlines');
+		$this->assertSame($key, ExternalStorageFactory::normalizePrivateKey(str_replace("\n", "\r\n", $key)), 'CRLF');
+		$this->assertSame($key, ExternalStorageFactory::normalizePrivateKey(rtrim($key)), 'no trailing newline');
+		$this->assertSame($key, ExternalStorageFactory::normalizePrivateKey(preg_replace('/^/m', '  ', $key)), 'indented');
+	}
+
+	public function testLeavesOtherFormatsAlone(): void {
+		$pem = "-----BEGIN RSA PRIVATE KEY-----\nProc-Type: 4,ENCRYPTED\nDEK-Info: DES-EDE3-CBC,FF44E0A94036766C\n\nAAAA\n-----END RSA PRIVATE KEY-----\n";
+		$this->assertSame($pem, ExternalStorageFactory::normalizePrivateKey($pem));
+		$this->assertSame('not a key', ExternalStorageFactory::normalizePrivateKey('not a key'));
+		$odd = "-----BEGIN OPENSSH PRIVATE KEY-----\\nAAAA\\n-----END OPENSSH PRIVATE KEY-----";
+		$this->assertSame($odd, ExternalStorageFactory::normalizePrivateKey($odd), 'not base64 inside: unchanged');
+	}
+}

tests/Unit/Backend/SftpRangeFetcherTest.php

@@ -0,0 +1,240 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\NgBackup\Tests\Unit\Backend;
+
+use OCA\NgBackup\Backend\SftpRangeFetcher;
+use OCA\NgBackup\Backend\SftpReadStream;
+use OCA\NgBackup\Tests\Unit\TempDirTrait;
+use PHPUnit\Framework\TestCase;
+
+require_once __DIR__ . '/SftpReadStreamTest.php'; // FakeSftpConnection, FakeSftpStorage
+
+/** SftpRangeFetcher against the fake SFTP server of SftpReadStreamTest, several connections at once. */
+class SftpRangeFetcherTest extends TestCase {
+	use TempDirTrait;
+
+	/** @var array<string, string> */
+	private array $files = [];
+
+	protected function setUp(): void {
+		SftpReadStream::reset();
+		for ($i = 0; $i < 10; $i++) {
+			$this->files["/home/repo/packs/p$i"] = random_bytes(3 * 1048576 + $i * 1000);
+		}
+	}
+
+	/** @return list<FakeSftpConnection> */
+	private function connections(int $n, array $options = []): array {
+		$result = [];
+		for ($c = 0; $c < $n; $c++) {
+			$result[] = new FakeSftpConnection($this->files, ...($options[$c] ?? []));
+		}
+		return $result;
+	}
+
+	/** @return list<object> what StorageBackend passes on: each with its SFTP channel open */
+	private static function opened(array $connections): array {
+		return array_map(fn (FakeSftpConnection $c): object => SftpReadStream::connection(new FakeSftpStorage($c)), $connections);
+	}
+
+	/** @return list<array{0:string, 1:int, 2:int}> */
+	private function ranges(): array {
+		$ranges = [];
+		for ($i = 0; $i < 10; $i++) {
+			$ranges[] = ["repo/packs/p$i", 1000 * $i, 2 * 1048576 + 333];
+		}
+		return $ranges;
+	}
+
+	/** @return array<int, string|null> sha1 of the contents by position (a failing comparison of MiBs would not fit in memory) */
+	private static function collect(\Generator $streams): array {
+		$result = [];
+		foreach ($streams as $i => $fh) {
+			$result[$i] = $fh === null ? null : sha1(stream_get_contents($fh));
+		}
+		return $result;
+	}
+
+	private function expected(array $ranges): array {
+		return array_map(fn (array $r): string => sha1(substr($this->files['/home/' . $r[0]], $r[1], $r[2])), $ranges);
+	}
+
+	public function testReadsEveryRangeInOrderOverAllConnections(): void {
+		$connections = $this->connections(4);
+		$ranges = $this->ranges();
+		$spool = $this->tempDir();
+
+		$this->assertSame($this->expected($ranges), self::collect(SftpRangeFetcher::fetch(self::opened($connections), '/home/', $ranges, $spool)));
+
+		foreach ($connections as $c) {
+			$this->assertGreaterThan(0, count($c->reads), 'every connection reads');
+			$this->assertLessThanOrEqual(SftpRangeFetcher::DEPTH, $c->maxInFlight);
+			$this->assertSame([], $c->openHandles);
+			$this->assertSame(0, $c->pending());
+			$this->assertTrue($c->disconnected, 'its own connections end with it');
+		}
+		$this->assertSame([], glob("$spool/*"), 'nothing left in the spool');
+	}
+
+	public function testKeepsSeveralRequestsInFlightOnEachConnection(): void {
+		$this->files['/home/repo/packs/big'] = random_bytes(10 * 1048576);
+		$connections = $this->connections(2);
+		self::collect(SftpRangeFetcher::fetch(self::opened($connections), '/home/', [['repo/packs/big', 0, 10 * 1048576], ['repo/packs/big', 5, 10 * 1048576 - 5]], $this->tempDir()));
+
+		$this->assertSame(SftpRangeFetcher::DEPTH, $connections[0]->maxInFlight);
+		$this->assertSame(SftpRangeFetcher::DEPTH, $connections[1]->maxInFlight);
+	}
+
+	public function testAnAnswerPhpseclibHasReadAlreadyIsTakenWithoutWaitingOnTheSocket(): void {
+		// The fake's answers are all "read already": its socket never becomes readable, and
+		// phpseclib's packet buffer holds data. Waiting on the socket would take a second a step.
+		$connections = $this->connections(2);
+		$sockets = [];
+		foreach ($connections as $c) {
+			$pair = stream_socket_pair(STREAM_PF_UNIX, STREAM_SOCK_STREAM, STREAM_IPPROTO_IP);
+			$sockets[] = $pair;
+			$c->fsock = $pair[0];
+			$c->packet_buffer = pack('N', 4) . 'more'; // a whole packet
+		}
+		$ranges = array_slice($this->ranges(), 0, 3);
+		$start = microtime(true);
+
+		$this->assertSame($this->expected($ranges), self::collect(SftpRangeFetcher::fetch(self::opened($connections), '/home/', $ranges, $this->tempDir())));
+
+		$this->assertLessThan(1.0, microtime(true) - $start);
+	}
+
+	public function testAServerThatCapsAReadStillGivesEveryByte(): void {
+		$connections = $this->connections(3, array_fill(0, 3, ['cap' => 100000]));
+		$ranges = $this->ranges();
+
+		$this->assertSame($this->expected($ranges), self::collect(SftpRangeFetcher::fetch(self::opened($connections), '/home/', $ranges, $this->tempDir())));
+		// learned: after the first short answers (and asking for their rest) it asks for no more than the server gives
+		foreach ($connections as $c) {
+			$this->assertLessThanOrEqual(2 * SftpRangeFetcher::DEPTH, count(array_filter($c->reads, fn (int $n): bool => $n > 100000)));
+		}
+	}
+
+	public function testAMissingFileIsLeftToTheCaller(): void {
+		$connections = $this->connections(2);
+		$ranges = $this->ranges();
+		$ranges[3][0] = 'repo/packs/gone';
+
+		$result = self::collect(SftpRangeFetcher::fetch(self::opened($connections), '/home/', $ranges, $this->tempDir()));
+
+		$expected = $this->expected($this->ranges());
+		$expected[3] = null;
+		$this->assertSame($expected, $result);
+		$this->assertSame([], $connections[0]->openHandles);
+	}
+
+	public function testARangePastTheEndOfTheFileIsLeftToTheCaller(): void {
+		$ranges = $this->ranges();
+		$ranges[5][2] = 10 * 1048576;
+
+		$result = self::collect(SftpRangeFetcher::fetch(self::opened($this->connections(2)), '/home/', $ranges, $this->tempDir()));
+
+		$this->assertNull($result[5]);
+		$this->assertSame($this->expected($this->ranges())[6], $result[6]);
+	}
+
+	public function testAServerErrorFailsOnlyThatRange(): void {
+		// every read from 1 MiB on fails on connection 0: its ranges, not those of the others
+		$connections = $this->connections(2, [['failAt' => 1048576]]);
+		$ranges = $this->ranges();
+
+		$result = self::collect(SftpRangeFetcher::fetch(self::opened($connections), '/home/', $ranges, $this->tempDir()));
+
+		$expected = $this->expected($ranges);
+		$failed = array_keys(array_filter($result, fn (?string $r): bool => $r === null));
+		$this->assertNotSame([], $failed);
+		foreach ($result as $i => $data) {
+			if ($data !== null) {
+				$this->assertSame($expected[$i], $data);
+			}
+		}
+		$this->assertLessThan(10, count($failed), 'the other connection goes on');
+		$this->assertSame([], $connections[0]->openHandles, 'a failed range is closed too');
+	}
+
+	public function testALostConnectionIsNotUsedAgainAndTheOthersGoOn(): void {
+		$connections = $this->connections(3, [['loseAt' => 1048576]]);
+		$ranges = $this->ranges();
+
+		$result = self::collect(SftpRangeFetcher::fetch(self::opened($connections), '/home/', $ranges, $this->tempDir()));
+
+		$expected = $this->expected($ranges);
+		$this->assertSame(1, count(array_filter($result, fn (?string $r): bool => $r === null)), 'only the range it was reading');
+		foreach ($result as $i => $data) {
+			if ($data !== null) {
+				$this->assertSame($expected[$i], $data);
+			}
+		}
+		$this->assertTrue($connections[0]->disconnected);
+		$this->assertLessThanOrEqual(1048576 / 261120 + SftpRangeFetcher::DEPTH + 1, count($connections[0]->reads), 'not used after it broke');
+	}
+
+	public function testWhenEveryConnectionIsLostTheRestIsLeftToTheCaller(): void {
+		$connections = $this->connections(2, [['throwAt' => 1048576], ['loseAt' => 1048576]]);
+
+		$result = self::collect(SftpRangeFetcher::fetch(self::opened($connections), '/home/', $this->ranges(), $this->tempDir()));
+
+		$this->assertSame(array_fill(0, 10, null), $result);
+	}
+
+	public function testABrokenConnectionIsReplacedAndTheRestIsReadAhead(): void {
+		$connections = $this->connections(1, [['loseAt' => 1048576]]);
+		$made = [];
+		$connect = function () use (&$made): object {
+			$made[] = $c = new FakeSftpConnection($this->files);
+			return SftpReadStream::connection(new FakeSftpStorage($c));
+		};
+		$ranges = $this->ranges();
+
+		$result = self::collect(SftpRangeFetcher::fetch(self::opened($connections), '/home/', $ranges, $this->tempDir(), $connect));
+
+		$expected = $this->expected($ranges);
+		$expected[0] = null; // the range it was reading when it broke: read the usual way
+		$this->assertSame($expected, $result);
+		$this->assertCount(1, $made);
+		$this->assertTrue($made[0]->disconnected, 'the new one ends with the fetcher too');
+	}
+
+	public function testConnectionsThatKeepBreakingAreReplacedOnlySoOften(): void {
+		$made = 0;
+		$connect = function () use (&$made): object {
+			$made++;
+			return SftpReadStream::connection(new FakeSftpStorage(new FakeSftpConnection($this->files, loseAt: 0)));
+		};
+		$ranges = array_merge($this->ranges(), $this->ranges(), $this->ranges());
+
+		$result = self::collect(SftpRangeFetcher::fetch(self::opened($this->connections(1, [['loseAt' => 0]])), '/home/', $ranges, $this->tempDir(), $connect));
+
+		$this->assertSame(array_fill(0, count($ranges), null), $result);
+		$this->assertSame(SftpRangeFetcher::MAX_RECONNECTS, $made);
+	}
+
+	public function testStoppingHalfwayEndsTheConnectionsAndLeavesNothingBehind(): void {
+		$connections = $this->connections(2);
+		$spool = $this->tempDir();
+		$streams = SftpRangeFetcher::fetch(self::opened($connections), '/home/', $this->ranges(), $spool);
+		$this->assertIsResource($streams->current());
+
+		unset($streams);
+
+		$this->assertTrue($connections[0]->disconnected);
+		$this->assertTrue($connections[1]->disconnected);
+		$this->assertSame([], glob("$spool/*"));
+	}
+
+	public function testReadsNoMoreThanAheadOfTheCaller(): void {
+		$connections = $this->connections(4);
+		$streams = SftpRangeFetcher::fetch(self::opened($connections), '/home/', $this->ranges(), $this->tempDir());
+		$streams->current();
+
+		$opened = array_sum(array_map(fn (FakeSftpConnection $c): int => count(array_unique(array_values($c->opened))), $connections));
+		$this->assertLessThanOrEqual(SftpRangeFetcher::AHEAD, $opened);
+	}
+}

tests/Unit/Backend/SftpReadStreamTest.php

@@ -0,0 +1,600 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\NgBackup\Tests\Unit\Backend;
+
+use OCA\NgBackup\Backend\BackendException;
+use OCA\NgBackup\Backend\SftpReadStream;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * SftpReadStream against a fake of the phpseclib connection: an SFTP server that answers READ
+ * requests from in-memory files, optionally capped. Every answer must be asked for by its request
+ * id, as phpseclib matches them: a server may answer out of order.
+ */
+class SftpReadStreamTest extends TestCase {
+	protected function setUp(): void {
+		SftpReadStream::reset();
+	}
+
+	public function testReadsAWholeFileWithSeveralRequestsInFlight(): void {
+		$data = random_bytes(5 * 1048576 + 12345);
+		$sftp = new FakeSftpConnection(['/home/repo/packs/ab/abcd' => $data]);
+		$fh = SftpReadStream::open(new FakeSftpStorage($sftp), 'repo/packs/ab/abcd');
+
+		$this->assertIsResource($fh);
+		$this->assertSame($data, stream_get_contents($fh));
+		$this->assertTrue(feof($fh));
+		fclose($fh);
+		$this->assertSame(SftpReadStream::DEPTH, $sftp->maxInFlight);
+		$this->assertSame(0, $sftp->pending(), 'nothing may be left on the connection after close');
+		$this->assertSame([], $sftp->openHandles);
+	}
+
+	public function testAServerThatCapsAReadStillGivesEveryByteInOrder(): void {
+		$data = random_bytes(3 * 1048576 + 7);
+		$sftp = new FakeSftpConnection(['/home/f' => $data], cap: 100000);
+		$fh = SftpReadStream::open(new FakeSftpStorage($sftp), 'f');
+
+		$this->assertSame($data, stream_get_contents($fh));
+		fclose($fh);
+		$this->assertSame(0, $sftp->pending());
+
+		// The cap is learned: a next stream asks for no more than the server gives.
+		$sftp->reads = [];
+		$fh = SftpReadStream::open(new FakeSftpStorage($sftp), 'f');
+		$this->assertSame($data, stream_get_contents($fh));
+		fclose($fh);
+		$this->assertSame([100000], array_values(array_unique($sftp->reads)));
+
+		// Only for that connection.
+		$other = new FakeSftpConnection(['/home/f' => $data]);
+		$fh = SftpReadStream::open(new FakeSftpStorage($other), 'f');
+		$this->assertSame($data, stream_get_contents($fh));
+		fclose($fh);
+		$this->assertSame(261120, max($other->reads));
+	}
+
+	public function testATinyAnswerDoesNotShrinkTheReadsBelowWhatEveryServerSupports(): void {
+		$data = random_bytes(1048576);
+		$sftp = new FakeSftpConnection(['/home/f' => $data], cap: 1000);
+		$fh = SftpReadStream::open(new FakeSftpStorage($sftp), 'f');
+		$this->assertSame($data, stream_get_contents($fh));
+		fclose($fh);
+		$this->assertSame(32768, min($sftp->reads));
+	}
+
+	public function testSeekingReadsFromTheNewOffset(): void {
+		$data = random_bytes(3 * 1048576);
+		$sftp = new FakeSftpConnection(['/home/f' => $data]);
+		$fh = SftpReadStream::open(new FakeSftpStorage($sftp), 'f');
+
+		$this->assertSame(0, fseek($fh, 2000000));
+		$this->assertSame(2000000, ftell($fh));
+		$this->assertSame(substr($data, 2000000, 1000), fread($fh, 1000));
+		$this->assertSame(0, fseek($fh, 10)); // backwards
+		$this->assertSame(substr($data, 10, 70000), $this->readExactly($fh, 70000));
+		$this->assertSame(0, fseek($fh, 100, SEEK_CUR)); // within what is already buffered
+		$this->assertSame(substr($data, 70110, 5000), $this->readExactly($fh, 5000));
+		fclose($fh);
+		$this->assertSame(0, $sftp->pending());
+	}
+
+	public function testASmallReadDoesNotFetchTheWholePipelineAhead(): void {
+		$sftp = new FakeSftpConnection(['/home/f' => random_bytes(10 * 1048576)]);
+		$fh = SftpReadStream::open(new FakeSftpStorage($sftp), 'f');
+		fread($fh, 100);
+		fclose($fh);
+		$this->assertCount(1, $sftp->reads, 'the first request goes alone, the pipeline grows while reading on');
+	}
+
+	public function testAnEmptyFileIsAtEndAtOnce(): void {
+		$sftp = new FakeSftpConnection(['/home/f' => '']);
+		$fh = SftpReadStream::open(new FakeSftpStorage($sftp), 'f');
+		$this->assertSame('', stream_get_contents($fh));
+		$this->assertTrue(feof($fh));
+		fclose($fh);
+	}
+
+	public function testAMissingFileCannotBeOpened(): void {
+		$sftp = new FakeSftpConnection([]);
+		$this->assertFalse(SftpReadStream::open(new FakeSftpStorage($sftp), 'nope'));
+		$this->assertSame(0, $sftp->pending());
+	}
+
+	public function testAServerErrorGoesOnWithTheStoragesOwnStreamFromTheSamePosition(): void {
+		$data = random_bytes(3 * 1048576);
+		$sftp = new FakeSftpConnection(['/home/f' => $data], failAt: 1048576);
+		$storage = new FakeSftpStorage($sftp);
+		$fh = SftpReadStream::open($storage, 'f');
+
+		$this->assertSame($data, $this->readAll($fh));
+		$this->assertSame(['f'], $storage->fopens);
+		$this->assertSame(strlen($data), ftell($fh));
+		fclose($fh);
+		$this->assertSame(0, $sftp->pending(), 'the connection is clean for the storage\'s own stream');
+		$this->assertSame([], $sftp->openHandles, 'the failed handle is closed');
+
+		// One failure is no reason to give up on the fast reads.
+		$fh = SftpReadStream::open($storage, 'f');
+		$this->assertIsResource($fh);
+		fclose($fh);
+	}
+
+	public function testOnlyFailuresInARowSwitchTheFastReadsOff(): void {
+		$data = random_bytes(2 * 1048576);
+		$failing = new FakeSftpStorage(new FakeSftpConnection(['/home/f' => $data], failAt: 1048576));
+		$working = new FakeSftpStorage(new FakeSftpConnection(['/home/f' => $data]));
+		for ($i = 1; $i < SftpReadStream::MAX_FAILURES; $i++) {
+			$fh = SftpReadStream::open($failing, 'f');
+			$this->assertSame($data, $this->readAll($fh));
+			fclose($fh);
+		}
+		$fh = SftpReadStream::open($working, 'f'); // a stream that works resets the count
+		$this->assertSame($data, $this->readAll($fh));
+		fclose($fh);
+		for ($i = 1; $i <= SftpReadStream::MAX_FAILURES; $i++) {
+			$fh = SftpReadStream::open($failing, 'f');
+			$this->assertIsResource($fh, "failure $i");
+			$this->assertSame($data, $this->readAll($fh));
+			fclose($fh);
+		}
+		$this->assertNull(SftpReadStream::open($working, 'f'));
+		$this->assertSame(SftpReadStream::MAX_FAILURES * 2 - 1, count($failing->fopens), 'every failed stream still gave all its data');
+	}
+
+	public function testAServerErrorAfterASeekGoesOnFromTheSeekedPosition(): void {
+		$data = random_bytes(3 * 1048576);
+		$sftp = new FakeSftpConnection(['/home/f' => $data], failAt: 2500000);
+		$storage = new FakeSftpStorage($sftp);
+		$fh = SftpReadStream::open($storage, 'f');
+		$this->assertSame(0, fseek($fh, 2400000));
+		$this->assertSame(substr($data, 2400000), $this->readAll($fh));
+		$this->assertSame(0, fseek($fh, 100)); // seeks go to the storage's stream now
+		$this->assertSame(substr($data, 100, 1000), $this->readExactly($fh, 1000));
+		fclose($fh);
+	}
+
+	public function testAConnectionErrorDoesNotFallBackOnTheSameConnection(): void {
+		// After an exception, answers may still be on their way; files_external's stream would
+		// take them for its own.
+		$sftp = new FakeSftpConnection(['/home/f' => random_bytes(3 * 1048576)], throwAt: 1048576);
+		$storage = new FakeSftpStorage($sftp);
+		$fh = SftpReadStream::open($storage, 'f');
+		$this->assertLessThan(3 * 1048576, strlen($this->readAll($fh)));
+		fclose($fh);
+		$this->assertSame([], $storage->fopens);
+	}
+
+	public function testALostConnectionDoesNotFallBackEither(): void {
+		$sftp = new FakeSftpConnection(['/home/f' => random_bytes(3 * 1048576)], loseAt: 1048576);
+		$storage = new FakeSftpStorage($sftp);
+		$fh = SftpReadStream::open($storage, 'f');
+		$this->assertLessThan(3 * 1048576, strlen($this->readAll($fh)));
+		fclose($fh);
+		$this->assertSame([], $storage->fopens);
+	}
+
+	public function testWhenTheStoragesOwnStreamFailsTooTheReadFails(): void {
+		$sftp = new FakeSftpConnection(['/home/f' => random_bytes(3 * 1048576)], failAt: 1048576);
+		$storage = new FakeSftpStorage($sftp, fopenFails: true);
+		$fh = SftpReadStream::open($storage, 'f');
+		$this->assertLessThan(3 * 1048576, strlen($this->readAll($fh)));
+		fclose($fh);
+		$this->assertSame(['f'], $storage->fopens);
+	}
+
+	public function testAConnectionErrorWhileOpeningIsAnErrorNotAMissingFile(): void {
+		// The OPEN request went out: the storage's own stream must not be tried on this connection.
+		$storage = new FakeSftpStorage(new FakeSftpConnection(['/home/f' => 'x'], throwAt: -1));
+		try {
+			SftpReadStream::open($storage, 'f');
+			$this->fail('expected a BackendException');
+		} catch (BackendException $e) {
+			$this->assertStringContainsString('connection', $e->getMessage());
+		}
+		$lost = new FakeSftpStorage(new FakeSftpConnection(['/home/f' => 'x'], loseAt: -1));
+		$this->expectException(BackendException::class);
+		SftpReadStream::open($lost, 'f');
+	}
+
+	public function testAConnectionErrorWhileOpeningDoesNotStopTheNextFile(): void {
+		try {
+			SftpReadStream::open(new FakeSftpStorage(new FakeSftpConnection(['/home/f' => 'x'], throwAt: -1)), 'f');
+		} catch (BackendException) {
+		}
+		$fh = SftpReadStream::open(new FakeSftpStorage(new FakeSftpConnection(['/home/f' => 'x'])), 'f');
+		$this->assertSame('x', stream_get_contents($fh));
+		fclose($fh);
+	}
+
+	public function testAFailedCloseDoesNotFallBackOnTheSameConnection(): void {
+		$sftp = new FakeSftpConnection(['/home/f' => random_bytes(3 * 1048576)], failAt: 1048576, closeFails: true);
+		$storage = new FakeSftpStorage($sftp);
+		$fh = SftpReadStream::open($storage, 'f');
+		$this->assertLessThan(3 * 1048576, strlen($this->readAll($fh)));
+		fclose($fh);
+		$this->assertSame([], $storage->fopens);
+	}
+
+	public function testAStorageThatThrowsIsNotUsed(): void {
+		$storage = new class {
+			public function getRoot(): string {
+				return '/';
+			}
+
+			public function getConnection(): object {
+				throw new \RuntimeException('Login failed');
+			}
+		};
+		$this->assertNull(SftpReadStream::open($storage, 'f'));
+	}
+
+	public function testReadManyReadsSmallFilesInBatches(): void {
+		$files = [];
+		for ($i = 0; $i < 70; $i++) {
+			// one empty file on purpose (random_bytes(0) throws)
+			$files["/home/index/$i"] = $i === 0 ? '' : random_bytes(random_int(1, 5000));
+		}
+		$files['/home/index/big'] = random_bytes(600000); // more than one READ
+		$sftp = new FakeSftpConnection($files);
+		$paths = array_map(fn ($p) => substr($p, 6), array_keys($files));
+
+		$got = SftpReadStream::readMany(new FakeSftpStorage($sftp), $paths);
+
+		$this->assertSame(array_combine($paths, array_values($files)), $got);
+		$this->assertSame(SftpReadStream::BATCH, $sftp->maxInFlight, 'a batch goes out at once');
+		$this->assertSame(0, $sftp->pending());
+		$this->assertSame([], $sftp->openHandles);
+	}
+
+	public function testReadManyLeavesAMissingOrFailingFileToTheCaller(): void {
+		$sftp = new FakeSftpConnection(['/home/a' => 'aaa', '/home/b' => random_bytes(400000), '/home/c' => 'ccc'], failAt: 300000);
+
+		$got = SftpReadStream::readMany(new FakeSftpStorage($sftp), ['a', 'missing', 'b', 'c']);
+
+		$this->assertSame(['a' => 'aaa', 'missing' => null, 'b' => null, 'c' => 'ccc'], $got);
+		$this->assertSame(0, $sftp->pending());
+		$this->assertSame([], $sftp->openHandles);
+	}
+
+	public function testReadManyAcrossACappedServer(): void {
+		$data = random_bytes(300000);
+		$sftp = new FakeSftpConnection(['/home/a' => $data, '/home/b' => 'b'], cap: 100000);
+		$this->assertSame(['a' => $data, 'b' => 'b'], SftpReadStream::readMany(new FakeSftpStorage($sftp), ['a', 'b']));
+	}
+
+	public function testReadManyEndsTheConnectionOnAConnectionError(): void {
+		// Answers to requests already out may still come: files_external must not get them.
+		$sftp = new FakeSftpConnection(['/home/a' => random_bytes(10), '/home/b' => 'b'], loseAt: 0);
+		try {
+			SftpReadStream::readMany(new FakeSftpStorage($sftp), ['a', 'b']);
+			$this->fail('expected a BackendException');
+		} catch (BackendException) {
+		}
+		$this->assertTrue($sftp->disconnected);
+	}
+
+	public function testReadManyStopsBatchingWhenCloseIsNotConfirmed(): void {
+		$files = [];
+		for ($i = 0; $i < 40; $i++) {
+			$files["/home/$i"] = "file $i";
+		}
+		$sftp = new FakeSftpConnection($files, closeStatus: 4);
+		$got = SftpReadStream::readMany(new FakeSftpStorage($sftp), array_map('strval', range(0, 39)));
+		$this->assertSame('file 0', $got['0']);
+		$this->assertSame('file 31', $got['31']);
+		$this->assertNull($got['32'], 'no second batch after unconfirmed closes');
+		$this->assertCount(SftpReadStream::BATCH, array_filter($got, fn ($v) => $v !== null));
+		// Nor on a later call over the same connection.
+		$this->assertNull(SftpReadStream::readMany(new FakeSftpStorage($sftp), ['0']));
+	}
+
+	public function testReadManyLeavesAMalformedAnswerToTheCaller(): void {
+		$sftp = new FakeSftpConnection(['/home/a' => 'aaaa', '/home/b' => 'bbbb'], malformed: '/home/a');
+		$this->assertSame(['a' => null, 'b' => 'bbbb'], SftpReadStream::readMany(new FakeSftpStorage($sftp), ['a', 'b']));
+		$this->assertSame([], $sftp->openHandles);
+	}
+
+	public function testReadManyOnAnUnsupportedConnectionIsNull(): void {
+		$this->assertNull(SftpReadStream::readMany(new \stdClass(), ['a']));
+		$this->assertNull(SftpReadStream::readMany(new FakeSftpStorage(new FakeSftpConnection(['/home/a' => 'a'], channelFails: true)), ['a']));
+	}
+
+	public function testAFreshConnectionHasItsSftpChannelOpenedFirst(): void {
+		// phpseclib 2 logs in at connect time but opens the SFTP channel on the first SFTP call.
+		$sftp = new FakeSftpConnection(['/home/config' => 'repository config']);
+		$this->assertFalse($sftp->initialised);
+		$fh = SftpReadStream::open(new FakeSftpStorage($sftp), 'config');
+		$this->assertIsResource($fh);
+		$this->assertSame('repository config', stream_get_contents($fh));
+		fclose($fh);
+	}
+
+	public function testAChannelThatCannotBeOpenedLeavesItToTheStoragesOwnStream(): void {
+		$sftp = new FakeSftpConnection(['/home/config' => 'x'], channelFails: true);
+		$this->assertNull(SftpReadStream::open(new FakeSftpStorage($sftp), 'config'));
+		$this->assertSame(0, $sftp->sent, 'nothing may be sent on a connection without an SFTP channel');
+	}
+
+	public function testAConnectionWithoutTheNeededMethodsIsNotUsed(): void {
+		$storage = new class {
+			public function getRoot(): string {
+				return '/';
+			}
+
+			public function getConnection(): object {
+				return new \stdClass();
+			}
+		};
+		$this->assertNull(SftpReadStream::open($storage, 'f'));
+		$this->assertNull(SftpReadStream::open(new \stdClass(), 'f'));
+	}
+
+	public function testAPhpseclib3ConnectionIsNotUsed(): void {
+		// phpseclib 3 has no _-prefixed methods; its packet_type and packet methods are private.
+		$v3 = new class {
+			private int $packet_type = -1;
+
+			private function _send_sftp_packet(): bool {
+				return true;
+			}
+
+			private function _get_sftp_packet(): string {
+				return '';
+			}
+
+			public function _realpath(string $path): string {
+				return $path;
+			}
+
+			public function realpath(string $path): string {
+				return $path . (string)$this->packet_type . $this->_send_sftp_packet() . $this->_get_sftp_packet();
+			}
+		};
+		$storage = new class($v3) {
+			public function __construct(
+				private object $connection,
+			) {
+			}
+
+			public function getRoot(): string {
+				return '/';
+			}
+
+			public function getConnection(): object {
+				return $this->connection;
+			}
+		};
+		$this->assertNull(SftpReadStream::open($storage, 'f'));
+	}
+
+	public function testAPrivatePacketTypeIsNotUsed(): void {
+		$conn = new class {
+			private int $packet_type = -1;
+
+			public function _send_sftp_packet(): bool {
+				return true;
+			}
+
+			public function _get_sftp_packet(): string {
+				return (string)$this->packet_type;
+			}
+
+			public function _realpath(string $path): string {
+				return $path;
+			}
+		};
+		$storage = new class($conn) {
+			public function __construct(
+				private object $connection,
+			) {
+			}
+
+			public function getRoot(): string {
+				return '/';
+			}
+
+			public function getConnection(): object {
+				return $this->connection;
+			}
+		};
+		$this->assertNull(SftpReadStream::open($storage, 'f'));
+	}
+
+	/** @param resource $fh */
+	private function readAll($fh): string {
+		$data = '';
+		while (!feof($fh)) {
+			$chunk = fread($fh, 65536);
+			if ($chunk === false || $chunk === '') {
+				break;
+			}
+			$data .= $chunk;
+		}
+		return $data;
+	}
+
+	/** @param resource $fh */
+	private function readExactly($fh, int $length): string {
+		$data = '';
+		while (strlen($data) < $length && !feof($fh)) {
+			$data .= fread($fh, $length - strlen($data));
+		}
+		return $data;
+	}
+}
+
+final class FakeSftpStorage {
+	/** @var list<string> paths opened through the storage's own stream */
+	public array $fopens = [];
+
+	public function __construct(
+		private FakeSftpConnection $connection,
+		private bool $fopenFails = false,
+	) {
+	}
+
+	/** files_external's own read stream: here the file from memory, seekable. */
+	public function fopen(string $path, string $mode) {
+		$this->fopens[] = $path;
+		$data = $this->connection->file('/home/' . $path);
+		if ($this->fopenFails || $data === null) {
+			return false;
+		}
+		$fh = fopen('php://memory', 'r+');
+		fwrite($fh, $data);
+		rewind($fh);
+		return $fh;
+	}
+
+	public function getRoot(): string {
+		return '/home/';
+	}
+
+	public function getConnection(): FakeSftpConnection {
+		return $this->connection;
+	}
+}
+
+/** The part of phpseclib\Net\SFTP (2.x) that SftpReadStream uses. */
+final class FakeSftpConnection {
+	public int $packet_type = -1;
+	public int $maxInFlight = 0;
+	/** @var list<int> lengths asked for by READ requests */
+	public array $reads = [];
+	/** @var array<string, string> */
+	public array $openHandles = [];
+	/** @var list<string> paths of every OPEN request */
+	public array $opened = [];
+	/** @var resource|null like phpseclib's socket (SftpRangeFetcher waits on it) */
+	public $fsock = null;
+	/** like phpseclib's: what came in with the last packet and is not read yet */
+	public string $packet_buffer = '';
+	/** Whether the SFTP channel is open: phpseclib 2 opens it on the first SFTP call. */
+	public bool $initialised = false;
+	/** Packets sent */
+	public int $sent = 0;
+	/** @var array<int, array{int, string}> answers by request id, in the order the server sent them */
+	private array $answers = [];
+	private int $handles = 0;
+
+	/** @param array<string, string> $files */
+	public function __construct(
+		private array $files,
+		private int $cap = 261120,
+		private ?int $failAt = null,
+		/** READ at or past this offset throws; -1: OPEN throws */
+		private ?int $throwAt = null,
+		/** READ at or past this offset finds the connection gone (phpseclib returns false); -1: OPEN */
+		private ?int $loseAt = null,
+		private bool $closeFails = false,
+		private bool $channelFails = false,
+		/** status code the server answers CLOSE with */
+		private int $closeStatus = 0,
+		/** a file whose DATA answers declare a wrong length */
+		private ?string $malformed = null,
+	) {
+	}
+
+	public bool $disconnected = false;
+
+	public function disconnect(): void {
+		$this->disconnected = true;
+	}
+
+	public function pwd(): string|false {
+		if ($this->channelFails) {
+			return false;
+		}
+		$this->initialised = true;
+		return '/home';
+	}
+
+	public function file(string $path): ?string {
+		return $this->files[$path] ?? null;
+	}
+
+	public function pending(): int {
+		return count($this->answers);
+	}
+
+	public function _realpath(string $path): string {
+		return '/' . trim(preg_replace('#/+#', '/', $path), '/');
+	}
+
+	public function _send_sftp_packet(int $type, string $data, int $id = 1): bool {
+		$this->sent++;
+		if (!$this->initialised) {
+			return false; // like phpseclib 2: no SFTP channel yet
+		}
+		switch ($type) {
+			case 3: // OPEN
+				if ($this->throwAt === -1) {
+					throw new \RuntimeException('Connection closed by server');
+				}
+				if ($this->loseAt === -1) {
+					return false;
+				}
+				$path = substr($data, 4, unpack('N', $data)[1]);
+				$this->opened[] = $path;
+				if (!isset($this->files[$path])) {
+					$this->answers[$id] = [101, pack('N', 2)];
+					break;
+				}
+				$handle = 'h' . ++$this->handles;
+				$this->openHandles[$handle] = $path;
+				$this->answers[$id] = [102, pack('Na*', strlen($handle), $handle)];
+				break;
+			case 4: // CLOSE
+				if ($this->closeFails) {
+					return false;
+				}
+				$handle = substr($data, 4, unpack('N', $data)[1]);
+				unset($this->openHandles[$handle]);
+				$this->answers[$id] = [101, pack('N', $this->closeStatus)];
+				break;
+			case 5: // READ
+				$len = unpack('N', $data)[1];
+				$handle = substr($data, 4, $len);
+				['hi' => $hi, 'lo' => $lo, 'n' => $n] = unpack('Nhi/Nlo/Nn', substr($data, 4 + $len));
+				$offset = $hi * 4294967296 + $lo;
+				$this->reads[] = $n;
+				if ($this->throwAt !== null && $this->throwAt >= 0 && $offset >= $this->throwAt) {
+					throw new \RuntimeException('Connection closed by server');
+				}
+				if ($this->loseAt !== null && $this->loseAt >= 0 && $offset >= $this->loseAt) {
+					$this->answers = [];
+					return false;
+				}
+				$file = $this->files[$this->openHandles[$handle]];
+				if ($this->failAt !== null && $offset >= $this->failAt) {
+					$this->answers[$id] = [101, pack('N', 4)]; // FX_FAILURE
+				} elseif ($offset >= strlen($file)) {
+					$this->answers[$id] = [101, pack('N', 1)]; // FX_EOF
+				} else {
+					$chunk = substr($file, $offset, min($n, $this->cap));
+					$declared = $this->openHandles[$handle] === $this->malformed ? strlen($chunk) + 7 : strlen($chunk);
+					$this->answers[$id] = [103, pack('Na*', $declared, $chunk)];
+				}
+				$this->maxInFlight = max($this->maxInFlight, count($this->answers));
+				break;
+			default:
+				throw new \LogicException("unexpected packet type $type");
+		}
+		return true;
+	}
+
+	public function _get_sftp_packet(?int $id = null): string|false {
+		if ($this->answers === []) {
+			throw new \LogicException('waiting for an answer that will never come');
+		}
+		if ($id === null || !isset($this->answers[$id])) {
+			throw new \LogicException("no answer for request $id");
+		}
+		[$this->packet_type, $payload] = $this->answers[$id];
+		unset($this->answers[$id]);
+		return $payload;
+	}
+}

tests/Unit/Backend/StorageBackendListTest.php

@@ -0,0 +1,113 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\NgBackup\Tests\Unit\Backend;
+
+use OCA\NgBackup\Backend\BackendException;
+use OCA\NgBackup\Backend\StorageBackend;
+use OCA\NgBackup\Tests\Unit\TempDirTrait;
+use OCP\Files\Storage\IStorage;
+use PHPUnit\Framework\TestCase;
+
+require_once __DIR__ . '/../../stubs/SmbStorage.php';
+
+/** On a remote storage every is_dir() is a round trip: listing index/ must not cost one per pack. */
+class StorageBackendListTest extends TestCase {
+	use TempDirTrait;
+
+	public function testListFilesChecksOnlyTheFolderItself(): void {
+		$dir = $this->tempDir();
+		foreach (['b1', 'a2', 'c3.part-0123abcd'] as $name) {
+			touch("$dir/$name");
+		}
+		$isDirCalls = 0;
+		$storage = $this->createMock(IStorage::class);
+		$storage->method('instanceOfStorage')->willReturn(false);
+		$storage->method('is_dir')->willReturnCallback(function (string $path) use (&$isDirCalls): bool {
+			$isDirCalls++;
+			return $path === 'repo' || $path === 'repo/index';
+		});
+		$storage->method('opendir')->willReturnCallback(fn (string $path) => $path === 'repo/index' ? opendir($dir) : false);
+
+		$backend = new StorageBackend($storage, 'repo');
+		$isDirCalls = 0; // the constructor checks the base folder
+		$this->assertSame(['index/a2', 'index/b1'], $backend->listFiles('index'));
+		$this->assertSame(1, $isDirCalls);
+
+		$isDirCalls = 0;
+		$this->assertSame(['index/a2', 'index/b1'], $backend->list('index'));
+		$this->assertSame(4, $isDirCalls, 'list() checks every entry: the reason listFiles() exists');
+	}
+
+	public function testListFilesOfAMissingFolderIsEmpty(): void {
+		$storage = $this->createMock(IStorage::class);
+		$storage->method('instanceOfStorage')->willReturn(false);
+		$storage->method('is_dir')->willReturnCallback(fn (string $path): bool => $path === 'repo');
+		$storage->expects($this->never())->method('opendir');
+		$this->assertSame([], (new StorageBackend($storage, 'repo'))->listFiles('snapshots'));
+	}
+
+	public function testAnUnreadableFolderIsAnErrorNotEmpty(): void {
+		$storage = $this->createMock(IStorage::class);
+		$storage->method('instanceOfStorage')->willReturn(false);
+		$storage->method('is_dir')->willReturn(true);
+		$storage->method('opendir')->willReturn(false);
+		$this->expectException(BackendException::class);
+		(new StorageBackend($storage, 'repo'))->listFiles('catalog');
+	}
+	public function testSmbFoldersAreListedInOneRequest(): void {
+		$calls = new \ArrayObject();
+		$share = new class($calls) {
+			public function __construct(private \ArrayObject $calls) {
+			}
+
+			public function dir(string $path): array {
+				$this->calls[] = "dir $path";
+				return array_map(fn (string $n) => new class($n, $this->calls) {
+					public function __construct(private string $n, private \ArrayObject $calls) {
+					}
+
+					public function getName(): string {
+						return $this->n;
+					}
+
+					public function isHidden(): bool {
+						$this->calls[] = "attributes {$this->n}";
+						return $this->n === 'desktop.ini';
+					}
+				}, ['b1', 'a2', '.hidden', 'desktop.ini', 'c3.part-0123abcd']);
+			}
+		};
+		$storage = $this->getMockBuilder(\OCA\Files_External\Lib\Storage\SMB::class)->disableOriginalConstructor()->getMock();
+		(fn () => $this->share = $share)->call($storage);
+		$storage->method('instanceOfStorage')->willReturn(false);
+		$storage->method('is_dir')->willReturn(true);
+		$storage->expects($this->never())->method('opendir');
+
+		$this->assertSame(['index/a2', 'index/b1'], (new StorageBackend($storage, 'repo'))->listFiles('index'));
+		$this->assertSame(['dir repo/index', 'attributes desktop.ini', 'attributes c3.part-0123abcd'], $calls->getArrayCopy(),
+			'only names a repository does not use cost a request');
+	}
+
+	public function testSmbWithAccessControlListsIsListedTheUsualWay(): void {
+		$dir = $this->tempDir();
+		touch("$dir/a1");
+		$storage = $this->getMockBuilder(\OCA\Files_External\Lib\Storage\SMB::class)->disableOriginalConstructor()->getMock();
+		(fn () => $this->checkAcl = true)->call($storage);
+		$storage->method('instanceOfStorage')->willReturn(false);
+		$storage->method('is_dir')->willReturn(true);
+		$storage->expects($this->once())->method('opendir')->willReturnCallback(fn () => opendir($dir));
+		$this->assertSame(['index/a1'], (new StorageBackend($storage, 'repo'))->listFiles('index'));
+	}
+
+	public function testSmbFallsBackToTheUsualListing(): void {
+		$dir = $this->tempDir();
+		touch("$dir/a1");
+		$storage = $this->getMockBuilder(\OCA\Files_External\Lib\Storage\SMB::class)->disableOriginalConstructor()->getMock(); // no share
+		$storage->method('instanceOfStorage')->willReturn(false);
+		$storage->method('is_dir')->willReturn(true);
+		$storage->method('opendir')->willReturnCallback(fn () => opendir($dir));
+		$this->assertSame(['index/a1'], (new StorageBackend($storage, 'repo'))->listFiles('index'));
+	}
+}

tests/Unit/Backend/StorageBackendReadAheadTest.php

@@ -0,0 +1,115 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\NgBackup\Tests\Unit\Backend;
+
+use OCA\NgBackup\Backend\SftpRangeFetcher;
+use OCA\NgBackup\Backend\SftpReadStream;
+use OCA\NgBackup\Backend\StorageBackend;
+use OCA\NgBackup\Tests\Unit\TempDirTrait;
+use OCP\Files\Storage\IStorage;
+use PHPUnit\Framework\TestCase;
+
+require_once __DIR__ . '/SftpReadStreamTest.php'; // FakeSftpConnection
+require_once __DIR__ . '/StorageBackendReconnectTest.php'; // SftpLikeStorage
+
+/** StorageBackend::readAhead(): over SFTP on connections of its own, built with the reconnect function. */
+class StorageBackendReadAheadTest extends TestCase {
+	use TempDirTrait;
+
+	/** @var list<FakeSftpConnection> */
+	private array $connections = [];
+	/** @var array<string, string> */
+	private array $files = [];
+	/** New storages after this many fail to connect. */
+	private ?int $connectLimit = null;
+
+	protected function setUp(): void {
+		SftpReadStream::reset();
+		for ($i = 0; $i < 6; $i++) {
+			$this->files["/home/base/repo/packs/p$i"] = random_bytes(1048576 + $i);
+		}
+	}
+
+	private function storage(): IStorage {
+		if ($this->connectLimit !== null && count($this->connections) >= $this->connectLimit) {
+			throw new \RuntimeException('Too many connections');
+		}
+		$sftp = new FakeSftpConnection($this->files);
+		$this->connections[] = $sftp;
+		$storage = $this->createMock(SftpLikeRootStorage::class);
+		$storage->method('instanceOfStorage')->willReturnCallback(fn (string $class): bool => $class === \OCA\Files_External\Lib\Storage\SFTP::class);
+		$storage->method('getConnection')->willReturn($sftp);
+		$storage->method('getRoot')->willReturn('/home/');
+		$storage->method('is_dir')->willReturn(true);
+		return $storage;
+	}
+
+	/** @return list<array{0:string, 1:int, 2:int}> */
+	private static function ranges(): array {
+		return array_map(fn (int $i): array => ["packs/p$i", 7, 1048576 - 7], range(0, 5));
+	}
+
+	public function testReadsAheadOnNewConnectionsOnly(): void {
+		$backend = new StorageBackend($this->storage(), 'base/repo', false, fn (): IStorage => $this->storage());
+		$backend->readAheadConnections = 4;
+		$this->assertTrue($backend->canReadAhead());
+
+		$result = [];
+		foreach ($backend->readAhead(self::ranges(), $this->tempDir()) as $i => $fh) {
+			$result[$i] = sha1(stream_get_contents($fh));
+		}
+
+		$expected = array_map(fn (int $i): string => sha1(substr($this->files["/home/base/repo/packs/p$i"], 7, 1048576 - 7)), range(0, 5));
+		$this->assertSame($expected, $result);
+		$this->assertCount(1 + 4, $this->connections);
+		$this->assertSame(0, $this->connections[0]->sent, 'the storage\'s own connection stays free');
+		foreach (array_slice($this->connections, 1) as $c) {
+			$this->assertTrue($c->disconnected);
+		}
+	}
+
+	public function testGoesOnWithTheConnectionsTheServerAllows(): void {
+		$this->connectLimit = 3;
+		$backend = new StorageBackend($this->storage(), 'base/repo', false, fn (): IStorage => $this->storage());
+		$backend->readAheadConnections = 4;
+
+		$count = 0;
+		foreach ($backend->readAhead(self::ranges(), $this->tempDir()) as $fh) {
+			$this->assertIsResource($fh);
+			$count++;
+		}
+
+		$this->assertSame(6, $count);
+		$this->assertCount(3, $this->connections);
+	}
+
+	public function testByDefaultOneConnectionNextToTheStoragesOwn(): void {
+		$backend = new StorageBackend($this->storage(), 'base/repo', false, fn (): IStorage => $this->storage());
+		foreach ($backend->readAhead(self::ranges(), $this->tempDir()) as $fh) {
+			$this->assertIsResource($fh);
+		}
+
+		$this->assertSame(1, SftpRangeFetcher::DEFAULT_CONNECTIONS);
+		$this->assertCount(2, $this->connections);
+	}
+
+	public function testNoNewConnectionMeansNoReadingAhead(): void {
+		$this->connectLimit = 1;
+		$backend = new StorageBackend($this->storage(), 'base/repo', false, fn (): IStorage => $this->storage());
+
+		$this->assertNull($backend->readAhead(self::ranges(), $this->tempDir()));
+	}
+
+	public function testWithoutAWayToConnectAgainItDoesNotReadAhead(): void {
+		$backend = new StorageBackend($this->storage(), 'base/repo', false, null);
+
+		$this->assertFalse($backend->canReadAhead());
+		$this->assertNull($backend->readAhead(self::ranges(), $this->tempDir()));
+	}
+}
+
+interface SftpLikeRootStorage extends SftpLikeStorage {
+	public function getRoot(): string;
+}

tests/Unit/Backend/StorageBackendReconnectTest.php

@@ -0,0 +1,169 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\NgBackup\Tests\Unit\Backend;
+
+use OCA\NgBackup\Backend\BackendException;
+use OCA\NgBackup\Backend\StorageBackend;
+use OCP\Files\Storage\IStorage;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * A Hetzner Storage Box drops an SFTP connection that carried a lot of data and then stayed
+ * quiet for a few minutes; files_external keeps using the dead client, on which every file
+ * looks missing. The backend builds the storage anew instead.
+ */
+class StorageBackendReconnectTest extends TestCase {
+	/** @var list<ReconnectFakeSftp> */
+	private array $connections = [];
+	/** New connections come up dead (the location is gone). */
+	private bool $deadOnArrival = false;
+
+	private function storage(): IStorage {
+		$sftp = new ReconnectFakeSftp();
+		$sftp->dropped = $this->deadOnArrival;
+		$this->connections[] = $sftp;
+		$storage = $this->createMock(SftpLikeStorage::class);
+		$storage->method('instanceOfStorage')->willReturnCallback(fn (string $class): bool => $class === \OCA\Files_External\Lib\Storage\SFTP::class);
+		$storage->method('getConnection')->willReturn($sftp);
+		$storage->method('is_dir')->willReturn(true);
+		$storage->method('file_exists')->willReturnCallback(fn (string $path): bool => $sftp->request() && $path === 'repo/config');
+		$storage->method('fopen')->willReturnCallback(function (string $path) use ($sftp) {
+			if (!$sftp->request() || $path !== 'repo/config') {
+				return false;
+			}
+			$fh = fopen('php://memory', 'w+b');
+			fwrite($fh, 'config');
+			rewind($fh);
+			return $fh;
+		});
+		return $storage;
+	}
+
+	private function backend(bool $reconnect = true): StorageBackend {
+		return new StorageBackend($this->storage(), 'repo', false, $reconnect ? fn (): IStorage => $this->storage() : null);
+	}
+
+	private static function idle(StorageBackend $backend): void {
+		(new \ReflectionProperty($backend, 'lastUsed'))->setValue($backend, microtime(true) - StorageBackend::IDLE_CHECK - 1);
+	}
+
+	public function testADeadConnectionIsReplacedAfterAPause(): void {
+		$backend = $this->backend();
+		$this->connections[0]->dropped = true;
+		self::idle($backend);
+		$this->assertTrue($backend->exists('config'));
+		$this->assertSame(1, $backend->reconnects);
+		$this->assertSame(1, $this->connections[0]->requests, 'only the check went over the old connection');
+	}
+
+	public function testAPauseOnALiveConnectionCostsOneCheck(): void {
+		$backend = $this->backend();
+		self::idle($backend);
+		$this->assertTrue($backend->exists('config'));
+		$this->assertSame(0, $backend->reconnects);
+		$this->assertSame(2, $this->connections[0]->requests);
+		$this->assertTrue($backend->exists('config'));
+		$this->assertSame(3, $this->connections[0]->requests, 'no check without a pause');
+	}
+
+	public function testAFailureOnAConnectionThatJustDiedIsRepeated(): void {
+		$backend = $this->backend();
+		$this->connections[0]->dropped = true; // without a pause: not checked first
+		$this->assertTrue($backend->exists('config'));
+		$fh = $backend->get('config');
+		$this->assertSame('config', stream_get_contents($fh));
+		$this->assertSame(1, $backend->reconnects);
+	}
+
+	public function testASilentlyDroppedConnectionIsReplacedAfterAPause(): void {
+		$backend = $this->backend();
+		$this->connections[0]->dropped = true;
+		$this->connections[0]->silent = true; // phpseclib still says connected
+		self::idle($backend);
+		$this->assertTrue($backend->exists('config'));
+		$this->assertSame(1, $backend->reconnects, 'the check failed, so the connection was replaced');
+	}
+
+	public function testAFailureOnASilentlyDroppedConnectionIsRepeated(): void {
+		$backend = $this->backend();
+		$this->connections[0]->dropped = true;
+		$this->connections[0]->silent = true;
+		$fh = $backend->get('config');
+		$this->assertSame('config', stream_get_contents($fh));
+		$this->assertSame(1, $backend->reconnects);
+	}
+
+	public function testAMissingFileOnALiveConnectionIsJustMissing(): void {
+		$backend = $this->backend();
+		$this->assertFalse($backend->exists('nothing'));
+		try {
+			$backend->get('nothing');
+			$this->fail('missing');
+		} catch (BackendException $e) {
+			$this->assertStringContainsString('Not found', $e->getMessage());
+		}
+		$this->assertSame(0, $backend->reconnects);
+		$this->assertCount(1, $this->connections);
+	}
+
+	public function testANewConnectionThatFailsToo(): void {
+		$backend = $this->backend();
+		$this->connections[0]->dropped = true;
+		$backend->exists('config'); // reconnects
+		$this->connections[1]->dropped = true;
+		$this->deadOnArrival = true;
+		self::idle($backend);
+		try {
+			$backend->get('config');
+			$this->fail('no connection');
+		} catch (BackendException) {
+		}
+		$this->assertSame(3, $backend->reconnects, 'once after the pause, once after the failure, no more');
+	}
+
+	public function testWithoutAWayToReconnectNothingChanges(): void {
+		$backend = $this->backend(false);
+		$this->connections[0]->dropped = true;
+		self::idle($backend);
+		$this->assertFalse($backend->exists('config'));
+		$this->assertCount(1, $this->connections);
+	}
+}
+
+interface SftpLikeStorage extends IStorage {
+	public function getConnection(): object;
+}
+
+/** The public phpseclib calls the backend uses to tell a dead connection. */
+final class ReconnectFakeSftp {
+	public bool $dropped = false;
+	/** Dropped without phpseclib noticing (as a Hetzner Storage Box does): it still says connected. */
+	public bool $silent = false;
+	private bool $connected = true;
+	public int $requests = 0;
+
+	public function isConnected(): bool {
+		return $this->connected;
+	}
+
+	public function clearStatCache(): void {
+	}
+
+	public function stat(string $path): array|false {
+		return $this->request() ? ['type' => 2] : false;
+	}
+
+	/** A request: false (and from then on disconnected) when the server has dropped the connection. */
+	public function request(): bool {
+		$this->requests++;
+		if ($this->dropped) {
+			if ($this->silent) {
+				return false;
+			}
+			$this->connected = false;
+		}
+		return $this->connected;
+	}
+}

tests/Unit/Command/TargetAddEstimateTest.php

@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\NgBackup\Tests\Unit\Command;
+
+use OCA\NgBackup\Command\TargetAdd;
+use PHPUnit\Framework\TestCase;
+
+class TargetAddEstimateTest extends TestCase {
+	public function testNoEstimateFromTheFirstFewFiles(): void {
+		// 4,568 index files, 10 in after 6 s: too few to say anything
+		$this->assertNull(TargetAdd::minutesLeft(6.0, 10, 4558, 4568));
+	}
+
+	public function testEstimateOnceEnoughFilesCameIn(): void {
+		// 300 files in 10 s: 4,268 left at 30 a second is about 2.4 minutes
+		$this->assertSame(3, TargetAdd::minutesLeft(10.0, 300, 4268, 4568));
+	}
+
+	public function testFivePercentOfASmallIndexIsEnough(): void {
+		// 6 of 100 files in 6 s: 94 left at one a second is about 1.6 minutes
+		$this->assertSame(2, TargetAdd::minutesLeft(6.0, 6, 94, 100));
+	}
+
+	public function testNoEstimateInTheFirstSecondsOrWhenDone(): void {
+		$this->assertNull(TargetAdd::minutesLeft(2.0, 500, 4000, 4500));
+		$this->assertNull(TargetAdd::minutesLeft(60.0, 4568, 0, 4568));
+	}
+}

tests/Unit/FormatTest.php

@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\NgBackup\Tests\Unit;
+
+use OCA\NgBackup\Format;
+use PHPUnit\Framework\TestCase;
+
+class FormatTest extends TestCase {
+	public function testDurationShowsDaysFromOneDayOn(): void {
+		$this->assertSame('00:00:00', Format::duration(-5));
+		$this->assertSame('12:10:13', Format::duration(12 * 3600 + 10 * 60 + 13));
+		$this->assertSame('1d 00:00:00', Format::duration(86400));
+		$this->assertSame('1d 12:10:13', Format::duration(86400 + 12 * 3600 + 10 * 60 + 13));
+	}
+
+	public function testTimeInZone(): void {
+		$t = (int)strtotime('2026-10-19 13:12:00 UTC');
+		$this->assertSame('2026-10-19 13:12', Format::time($t, 'UTC'));
+		$this->assertSame('2026-10-19 15:12', Format::time($t, 'Europe/Berlin')); // summer time
+		$this->assertSame('2026-12-01 01:00', Format::time((int)strtotime('2026-12-01 00:00:00 UTC'), 'Europe/Amsterdam'));
+	}
+}

tests/Unit/Job/BackupProgressTest.php

@@ -0,0 +1,48 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\NgBackup\Tests\Unit\Job;
+
+use OCA\NgBackup\Job\BackupRun;
+use PHPUnit\Framework\TestCase;
+
+class BackupProgressTest extends TestCase {
+	public function testCountsFinishedFilesAndTheFileBeingRead(): void {
+		$state = ['phase' => 'files', 'estimate' => ['bytes' => 1000, 'approximate' => false],
+			'stats' => ['bytes' => 500], 'cur' => ['offset' => 180]];
+		$this->assertSame(['fraction' => 0.68, 'approximate' => false], BackupRun::progress($state));
+	}
+
+	public function testStaysBelowHundredPercentWhenTheEstimateIsTooLow(): void {
+		$state = ['phase' => 'files', 'estimate' => ['bytes' => 1000, 'approximate' => true], 'stats' => ['bytes' => 5000], 'cur' => null];
+		$this->assertSame(['fraction' => 0.99, 'approximate' => true], BackupRun::progress($state));
+	}
+
+	public function testNoProgressWithoutEstimateOrOutsideTheFilesPhase(): void {
+		$this->assertNull(BackupRun::progress(['phase' => 'files', 'stats' => ['bytes' => 1]]));
+		$this->assertNull(BackupRun::progress(['phase' => 'files', 'estimate' => ['bytes' => 0, 'approximate' => true], 'stats' => ['bytes' => 1]]));
+		$this->assertNull(BackupRun::progress(['phase' => 'commit', 'estimate' => ['bytes' => 10, 'approximate' => false], 'stats' => ['bytes' => 1]]));
+	}
+
+	private static function runIn(string $phase, array $state, string $status = \OCA\NgBackup\Db\Run::RUNNING): \OCA\NgBackup\Db\Run {
+		$run = new \OCA\NgBackup\Db\Run();
+		$run->setStatus($status);
+		$run->setPhase($phase);
+		$run->setState(json_encode($state, JSON_THROW_ON_ERROR));
+		return $run;
+	}
+
+	public function testDatabasePhaseCountsTheTablesDumped(): void {
+		$run = self::runIn('db', ['dump' => ['tables' => array_fill(0, 183, 'oc_t'), 'i' => 47]]);
+		$this->assertSame(['fraction' => 47 / 183, 'approximate' => false, 'tables' => 47, 'totalTables' => 183], BackupRun::progressOf($run));
+	}
+
+	public function testDatabasePhaseHasNoFigureBeforeItsFirstStep(): void {
+		$this->assertNull(BackupRun::progressOf(self::runIn('db', ['files' => []])));
+	}
+
+	public function testNoProgressForAFinishedRun(): void {
+		$this->assertNull(BackupRun::progressOf(self::runIn('db', ['dump' => ['tables' => ['oc_a'], 'i' => 0]], \OCA\NgBackup\Db\Run::DONE)));
+	}
+}

tests/Unit/Job/BackupRunTest.php

@@ -27,13 +27,14 @@ class BackupRunTest extends TestCase {
 
 		$state = BackupRun::start($src);
 		$steps = 0;
-		while ($state['phase'] !== 'done' && $steps < 500) {
+		while ($state['phase'] !== 'commit' && $steps < 500) {
 			// Fresh repository object per step, state through JSON: as separate processes would.
 			$repo = Repository::openWithKey($backend, $keys);
 			$state = json_decode(json_encode(BackupRun::step($repo, $state, microtime(true) + 0.05)), true);
 			$steps++;
 		}
-		$this->assertSame('done', $state['phase']);
+		$this->assertSame('commit', $state['phase']);
+		Repository::openWithKey($backend, $keys)->recordSnapshot($state['snapshot']);
 		$this->assertGreaterThan(2, $steps, 'the run was actually split into steps');
 
 		$target = $this->tempDir();
@@ -41,6 +42,61 @@ class BackupRunTest extends TestCase {
 		$this->assertSame(self::hashTree($src), self::hashTree($target));
 	}
 
+	public function testTheSnapshotIsWrittenInAStepOfItsOwnFromAllSegmentsAtOnce(): void {
+		$src = $this->tempDir();
+		for ($i = 0; $i < 60; $i++) {
+			file_put_contents("$src/f$i.txt", random_bytes(200000));
+		}
+		$backend = new RangeCountingBackend(new LocalBackend($this->tempDir()));
+		$keys = KeyRing::generate();
+		Repository::initWithKey($backend, $keys, $keys->wrap('pw'));
+
+		$state = BackupRun::start($src);
+		for ($i = 0; $i < 500 && $state['phase'] === 'files'; $i++) {
+			$state = BackupRun::step(Repository::openWithKey($backend, $keys), $state, microtime(true) + 0.01);
+		}
+		$this->assertSame('finish', $state['phase'], 'the step that read the last file does not write the snapshot');
+		$this->assertGreaterThan(2, count($state['segments']));
+		$backend->batches = [];
+
+		$state = BackupRun::step(Repository::openWithKey($backend, $keys), $state, microtime(true) + 0.01);
+
+		$this->assertSame('commit', $state['phase']);
+		// One batch; the blobs of a segment follow each other in its pack and are one read.
+		$this->assertSame([count($state['segments'])], $backend->batches);
+		Repository::openWithKey($backend, $keys)->recordSnapshot($state['snapshot']);
+		$target = $this->tempDir();
+		Repository::openWithKey($backend, $keys)->restore($state['snapshot'], $target);
+		$this->assertSame(self::hashTree($src), self::hashTree($target));
+	}
+
+	public function testBlobsThatFollowEachOtherInAPackAreReadAsOneRange(): void {
+		$backend = new RangeCountingBackend(new LocalBackend($this->tempDir()));
+		$keys = KeyRing::generate();
+		$repo = Repository::initWithKey($backend, $keys, $keys->wrap('pw'));
+		$stats = [];
+		$segments = [];
+		$expected = [];
+		for ($s = 0; $s < 3; $s++) {
+			$writer = new \OCA\NgBackup\Repository\BlobWriter(fn (string $data): string => $repo->storeData($data, $stats), 1000);
+			$lines = [];
+			for ($i = 0; $i < 100; $i++) {
+				$lines[] = json_encode(['segment' => $s, 'line' => $i, 'pad' => bin2hex(random_bytes(20))]);
+			}
+			$writer->write(implode("\n", $lines) . "\n");
+			$segments[] = $writer->finish();
+			$repo->flushPacks(); // one pack per segment, as one per step
+			array_push($expected, ...$lines);
+		}
+		$this->assertGreaterThan(3, count(array_merge(...$segments)));
+		$backend->batches = [];
+
+		$read = iterator_to_array(Repository::openWithKey($backend, $keys)->readLines(array_merge(...$segments)), false);
+
+		$this->assertSame($expected, array_values(array_filter($read, fn (string $l): bool => $l !== '')));
+		$this->assertSame([3], $backend->batches, 'one read per segment, all in one batch');
+	}
+
 	public function testFileChangedBetweenStepsIsReadAgain(): void {
 		$src = $this->tempDir();
 		file_put_contents("$src/big.bin", random_bytes(20 * 1048576));
@@ -50,7 +106,7 @@ class BackupRunTest extends TestCase {
 
 		$state = BackupRun::start($src);
 		$mutated = false;
-		for ($i = 0; $i < 500 && $state['phase'] !== 'done'; $i++) {
+		for ($i = 0; $i < 500 && $state['phase'] !== 'commit'; $i++) {
 			$state = BackupRun::step(Repository::openWithKey($backend, $keys), $state, microtime(true) + 0.01);
 			if (!$mutated && $state['cur'] !== null && $state['cur']['offset'] > 0) {
 				$fh = fopen("$src/big.bin", 'r+b');
@@ -60,6 +116,8 @@ class BackupRunTest extends TestCase {
 				$mutated = true;
 			}
 		}
+		$this->assertSame('commit', $state['phase']);
+		Repository::openWithKey($backend, $keys)->recordSnapshot($state['snapshot']);
 		$this->assertTrue($mutated);
 		$this->assertGreaterThanOrEqual(1, $state['stats']['retried'] ?? 0);
 		$target = $this->tempDir();
@@ -78,14 +136,17 @@ class BackupRunTest extends TestCase {
 		Repository::initWithKey($backend, $keys, $keys->wrap('pw'));
 		$run = function (?string $parent) use ($backend, $src, $keys): array {
 			$state = BackupRun::start(['data' => $src], $parent);
-			for ($i = 0; $i < 2000 && $state['phase'] !== 'done'; $i++) {
+			for ($i = 0; $i < 2000 && $state['phase'] !== 'commit'; $i++) {
 				$state = json_decode(json_encode(BackupRun::step(Repository::openWithKey($backend, $keys), $state, microtime(true))), true);
 			}
+			if ($state['phase'] === 'commit') {
+				Repository::openWithKey($backend, $keys)->recordSnapshot($state['snapshot']);
+			}
 			return $state;
 		};
 		$first = $run(null);
 		$second = $run($first['snapshot']);
-		$this->assertSame('done', $second['phase']);
+		$this->assertSame('commit', $second['phase']);
 		$this->assertGreaterThan(150, $second["steps"], "one file per step");
 		$this->assertSame(0, $second['stats']['read'], 'merge-join with the parent across steps reuses every file');
 		$this->assertSame(200, $second['stats']['reused']);
@@ -94,3 +155,54 @@ class BackupRunTest extends TestCase {
 		$this->assertSame(self::hashTree($src), self::hashTree("$target/data"));
 	}
 }
+
+final class RangeCountingBackend implements \OCA\NgBackup\Backend\IBackend {
+	use \OCA\NgBackup\Backend\GetsOneByOne {
+		getRanges as private oneByOne;
+	}
+
+	/** @var list<int> number of ranges per getRanges() call */
+	public array $batches = [];
+
+	public function __construct(
+		private \OCA\NgBackup\Backend\IBackend $inner,
+	) {
+	}
+
+	public function getRanges(array $ranges): \Generator {
+		$this->batches[] = count($ranges);
+		return $this->oneByOne($ranges);
+	}
+
+	public function put(string $path, $stream): void {
+		$this->inner->put($path, $stream);
+	}
+
+	public function get(string $path) {
+		return $this->inner->get($path);
+	}
+
+	public function getRange(string $path, int $offset, int $length): string {
+		return $this->inner->getRange($path, $offset, $length);
+	}
+
+	public function exists(string $path): bool {
+		return $this->inner->exists($path);
+	}
+
+	public function move(string $from, string $to): void {
+		$this->inner->move($from, $to);
+	}
+
+	public function list(string $prefix): array {
+		return $this->inner->list($prefix);
+	}
+
+	public function listFiles(string $dir): array {
+		return $this->inner->listFiles($dir);
+	}
+
+	public function delete(string $path): void {
+		$this->inner->delete($path);
+	}
+}

tests/Unit/Repository/CrashSafetyTest.php

@@ -0,0 +1,106 @@
+<?php
+
+declare(strict_types=1);
+
+// SPDX-FileCopyrightText: 2026 Dillard Blom
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+namespace OCA\NgBackup\Tests\Unit\Repository;
+
+use OCA\NgBackup\Backend\LocalBackend;
+use OCA\NgBackup\Crypto\KeyRing;
+use OCA\NgBackup\Job\BackupRun;
+use OCA\NgBackup\Repository\Repository;
+use OCA\NgBackup\Repository\RepositoryException;
+use OCA\NgBackup\Tests\Unit\TempDirTrait;
+use PHPUnit\Framework\TestCase;
+
+/** Data-safety cases found in the pre-beta review. */
+class CrashSafetyTest extends TestCase {
+	use TempDirTrait;
+
+	public function testListingKeepsNamesThatOnlyLookLikeTemporaryFiles(): void {
+		$root = $this->tempDir();
+		$backend = new LocalBackend($root);
+		mkdir("$root/users/john.part-time", 0700, true);
+		file_put_contents("$root/users/john.part-time/20261006T120000Z-aaaa0001", 'x');
+		file_put_contents("$root/users/upload.part-deadbeef", 'partial');
+		$this->assertSame(['users/john.part-time/20261006T120000Z-aaaa0001'], $backend->list('users'));
+	}
+
+	public function testPruneStopsWhenARecordedExportManifestIsMissing(): void {
+		$root = $this->tempDir();
+		$backend = new LocalBackend($root);
+		$keys = KeyRing::generate();
+		$repo = Repository::initWithKey($backend, $keys, $keys->wrap('pw'));
+		$stats = [];
+		$blob = $repo->storeData(random_bytes(1000), $stats);
+		$repo->flushPacks();
+		$path = 'users/alice/20261006T120000Z-aaaa0001';
+		$repo->putObject($path, json_encode(['uid' => 'alice', 'entries' => ['f.txt' => ['t' => 'f', 'b' => [$blob], 's' => 1000]]]));
+		$repo->recordUserExport($path);
+		unlink("$root/$path");
+
+		$packsBefore = $backend->list('packs');
+		try {
+			Repository::openWithKey($backend, $keys)->prune();
+			$this->fail('prune must refuse while a recorded export is missing');
+		} catch (RepositoryException $e) {
+			$this->assertStringContainsString('missing on the location', $e->getMessage());
+		}
+		$this->assertSame($packsBefore, $backend->list('packs'), 'no pack was deleted');
+	}
+
+	public function testForgetAndUntrashKeepTheSnapshotRestorable(): void {
+		$src = $this->tempDir();
+		file_put_contents("$src/a.txt", 'hello');
+		$root = $this->tempDir();
+		$backend = new LocalBackend($root);
+		$keys = KeyRing::generate();
+		Repository::initWithKey($backend, $keys, $keys->wrap('pw'));
+		$state = BackupRun::start($src);
+		while ($state['phase'] !== 'commit') {
+			$state = BackupRun::step(Repository::openWithKey($backend, $keys), $state, microtime(true) + 5);
+		}
+		Repository::openWithKey($backend, $keys)->recordSnapshot($state['snapshot']);
+		$id = $state['snapshot'];
+
+		Repository::openWithKey($backend, $keys)->forget($id, 'test');
+		$repo = Repository::openWithKey($backend, $keys);
+		$this->assertSame([], $repo->listSnapshots());
+		$this->assertArrayHasKey($id, $repo->trash());
+		$this->assertFalse($backend->exists('snapshots/' . $id), 'original removed after the catalog switch');
+
+		$repo->untrash($id);
+		$repo = Repository::openWithKey($backend, $keys);
+		$this->assertSame([$id], $repo->listSnapshots());
+		$this->assertSame([], $repo->trash());
+		$target = $this->tempDir();
+		$repo->restore($id, $target);
+		$this->assertSame('hello', file_get_contents("$target/a.txt"));
+	}
+
+	public function testFileThatKeepsChangingDoesNotStallTheRun(): void {
+		$src = $this->tempDir();
+		file_put_contents("$src/live.db", random_bytes(3 * Repository::BLOB_SIZE));
+		$root = $this->tempDir();
+		$backend = new LocalBackend($root);
+		$keys = KeyRing::generate();
+		Repository::initWithKey($backend, $keys, $keys->wrap('pw'));
+
+		$state = BackupRun::start($src);
+		$n = 0;
+		for ($i = 0; $i < 50 && $state['phase'] !== 'commit'; $i++) {
+			$state = BackupRun::step(Repository::openWithKey($backend, $keys), $state, microtime(true) + 0.001);
+			// Rewrite the file after every step: it never stays the same between two steps.
+			$fh = fopen("$src/live.db", 'r+b');
+			fwrite($fh, random_bytes(16));
+			fclose($fh);
+			touch("$src/live.db", time() + ++$n);
+			clearstatcache();
+		}
+		$this->assertSame('commit', $state['phase'], 'the run finishes instead of retrying forever');
+		$this->assertSame(1, $state['stats']['changing'] ?? 0);
+		$this->assertSame(['live.db'], BackupRun::warnings($state)['changing']);
+	}
+}