Why does the repo 'stale lock' between backup and forget operations

[ilium007]

I had a backup that ran over 46hrs but then failed between backup and forget operations stating 'stale lock'. I ran an unlock on the repo and re-ran backup and it ran without error.

Was it just because the lock was over 1hr old?

scan finished in 185.828s: 194610 files, 1.418 TiB
[10:24:10] 59.72%  292 files 866.989 GiB, total 194610 files 1.418 TiB, 0 errors ETA 40:05:02
[22:11:02] 72.08%  363 files 1.022 TiB, total 194610 files 1.418 TiB, 0 errors ETA 30:21:13
[35:49:03] 85.86%  446 files 1.217 TiB, total 194610 files 1.418 TiB, 0 errors ETA 13:52:39

Files:       194610 new,     0 changed,     0 unmodified
Dirs:        32117 new,     0 changed,     0 unmodified
Data Blobs:  608846 new
Tree Blobs:  28949 new
Added to the repository: 673.656 GiB (667.372 GiB stored)

processed 194610 files, 1.418 TiB in 45:53:02
snapshot 941a6857 saved
2024/10/07 21:29:56 profile 'storage01': finished 'backup'
2024/10/07 21:29:56 profile 'storage01': cleaning up repository using retention information
repository d3d6bbe8 opened (version 2, compression level auto)
repo already locked, waiting up to 0s for the lock
unable to create lock in backend: repository is already locked by PID 489849 on debian01 by root (UID 0, GID 0)
lock was created at 2024-10-05 22:14:51 (46h15m7.177865848s ago)
storage ID db7302c6
the `unlock` command can be used to remove stale locks
2024/10/07 21:29:58 restic: possible stale lock detected (lock age 46h15m7.177s >= 1h0m0s). Set `force-inactive-lock` to `true` to enable automatic unlocking of stale locks.
2024/10/07 21:29:58 backup retention on profile 'storage01': exit status 11

[creativeprojects]

To be honest I'm not sure why it happened. I never had a backup running for so long so I can't compare.

Maybe the target storage was slow to delete the lock because there were many operations to finish? (in case you're using a target with an async API for example?)

[ilium007]

I'm running Rest rest server in Docker. When I re-ran the job it ran fine.