Nextcloud 35 reads keys with phpseclib 3, which refuses an OpenSSH-format
key whose line breaks were lost ("Unable to read key"); phpseclib 2 on
Nextcloud 34 read it. The key is fixed when used, so stored locations work
again without re-entering it.
A restore read one pack at a time over one SFTP connection, which over a long
line is bound by the round trip and by what one TCP connection gets: about
2-3 MiB/s from a Hetzner Storage Box to Canada, with PHP mostly waiting.
Repository::restore() now first lists the ranges of packs the restore needs,
in order (ReadAheadPlan), and the location reads them ahead into unlinked
files in a spool folder in the target (IReadsAhead). Over SFTP,
SftpRangeFetcher does that on four connections of its own, 16 requests in
flight each, taking the answers of whichever connection has one. A range that
fails, a damaged copy, or a blob that moved since the plan is read the usual
way, which reports what is wrong. Other locations restore as before.
On a test line with 120 ms RTT and 0.2% loss, a 1.6 GiB restore went from
5.1 to 17.8 MiB/s, all files identical.
Each 30-second step opened the location again and read its list of
index files. Over SMB that cost a request per file, so on a large
repository opening took longer than the step: each step stored one
4 MiB pack and the list grew further. A first backup of nc01 to a
Storage Box over SMB managed 12 GiB in 35 hours.
occ backup:run and system cron now keep the repository open for the
whole run (reopened when another process took a step or the location
was edited), opening no longer counts towards the step's time, and
SMB folders are listed in one request.
occ backup:cancel stops a running backup: no new step starts and the
step in progress finishes first. A run of an earlier version, which
does not hold back its next step, is marked cancelled after two
minutes unless it is recording its snapshot.
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. StorageBackend now checks the
connection after a minute without requests, and replaces a connection that
is dead after a failed request (once per request; put, move and delete are
not repeated). SftpReadStream closes a connection it left in an unknown state.
The verify cache refresh took more than 6 minutes on PostgreSQL for 27,547
packs, one autocommitted insert per pack: putMany()/replaceAll() write in one
transaction. After a verify the cache holds the index files as they are, so a
blob in two packs stays cached for both.
files_external's SFTP read stream asks for the next 256 KiB only after
the previous answer has arrived, so reading costs one round trip per
request whatever the line speed: 4.9 MB/s at 47 ms to a Hetzner Storage
Box. SftpReadStream keeps up to eight READ requests in flight over the
same phpseclib connection (15 MB/s on that link), starting with one so
a small read does not fetch megabytes ahead.
A server that answers less than asked is handled by asking again from
where the answer ended; when more data follows, that size is used for
later reads over the same connection, never below the 32 KiB every
server must support. Without the needed connection methods, or when the
open fails, the storage's own stream is used as before.
Opening a repository lists index/, which holds one file per pack.
StorageBackend::list() checked every entry with is_dir(), and on a
remote storage each check is a round trip. Over SFTP to a Hetzner Storage
Box (33 ms) with a 60 GiB repository, occ backup:run (30 s steps) spent
nearly every step on these requests and uploaded 45 KiB/s; with this
change it uploads 5.8 MB/s. The cost grows with the number of packs.
index/, snapshots/, catalog/ and trash/info/ only ever hold objects:
list them with the new IBackend::listFiles(), one listing without
per-entry checks.
dillard