Not able to create backup: no lock found

[seb2010]

Hi guys,

I am not able to solve an issue with my backup task. I just won't finish in snapshot mode.
I do get the following log output:

INFO: starting new backup job: vzdump 101 --node SJSERVER --compress zstd --tmpdir /mnt/usb --all 0 --fleecing 0 --mode snapshot --notes-template '{{guestname}}' --storage USB
INFO: Starting Backup of VM 101 (lxc)
INFO: Backup started at 2025-05-09 08:25:43
INFO: status = running
INFO: CT Name: wschi
INFO: including mount point rootfs ('/') in backup
INFO: backup mode: snapshot
INFO: ionice priority: 7
INFO: no lock found trying to remove any lock
INFO: create storage snapshot 'vzdump'
no lock found trying to remove 'backup'  lock
ERROR: Backup of VM 101 failed - no lock found trying to remove 'backup'  lock
INFO: Failed at 2025-05-09 08:25:44
INFO: Backup job finished with errors
job errors

I have 2 VMs, one 64GB, one 128GB, the thin-pool they are on has 156GB of free space, the root directory has 112GB of free space and I also have an USB-drive with 128GB of free space.
No matter which storage target I use (local, USB or a remote rclone-mounted gdrive location) I do get the same errors. Suspend mode is working rhough, but not reliably and it is not the desired mode.

I already tried removing all stale lock files in /var/lock and removed orphaned dump-files. I also unlocked all to-be-backed-up Container with pct unlock.

How can I investigate the issue and solve it?

Kind regard and thanks for your help in advance,
SEB

 

[fabian]

the lock the log is referring to is the one inside the config file of the guest that the backup task itself sets.. do you have any scripts running that might remove such locks for whatever reason?

 

[seb2010]

oh god! YES, that was it. I was having trouble that backups where failing constantly due to (as it seemed) orphaned locks. Therefor I added pct unlock commands in a hook script on backup start. But this destroyed the intention of the the backup task to lock the container and thus was not able to positively verify the lock.
My fault, sorry guys and thank you @fabian for the hint!!!