LXC backup failed and stop ct

[abranca]

Hi,
It happens randomly that the backup (ZSTD in snapshot mode) of a container fails and the container itself is shut down.

I use a networked QNAP connected to PVE 6.2-6 in CIFS.

The error that is returned to me is as follows:

INFO: starting new backup job: vzdump 101 --mode snapshot --storage kve-pmg --quiet 1 --mailto xxxxxx@yyyyyy.com --mailnotification always --compress zstd
INFO: filesystem type on dumpdir is 'cifs' -using /var/tmp/vzdumptmp5168 for temporary files
INFO: Starting Backup of VM 101 (lxc)
INFO: Backup started at 2020-10-18 20:00:03
INFO: status = stopped
ERROR: Backup of VM 101 failed - CT is locked (snapshot-delete)
INFO: Failed at 2020-10-18 20:00:03
INFO: Backup job finished with errors

TASK ERROR: job errors

Has this problem already happened to others?
What checks can I do? It is the only container to which this problem happens.

thanks to everyone

 

[Stefan_R]

You see the error message right in your log:

ERROR: Backup of VM 101 failed - CT is locked (snapshot-delete)

That means that you tried to delete a snapshot of that container at the same time. Don't do that and the backup should work

If your container is stuck with the lock (i.e. you're absolutely 100% certain you are *not* deleting a snapshot at the moment) you can try 'pct unlock <vmid>' to force unlock it. That should not usually be necessary though.

 

[abranca]

Thanks Stefan for your reply!

That means that you tried to delete a snapshot of that container at the same time. Don't do that and the backup should work

I saw that error but the backup is programmed and happens automatically.
So, the problem is that the backup starts while it is deleting an old one?

In the settings of the storage (connected in CIFS) I set the number of backups to keep to 2. I have no infinite space unfortunately.
Can it be a problem with the CIFS connection? Is it worth connecting the network storage with NFS or other protocol?

Thanks for your availability

 

[Stefan_R]

No, a snapshot is not a backup. It is a storage snapshot, "Snapshots" tab in the GUI. What "Status" does your container report in the GUI? (or 'pct list')

 

[abranca]

Okay, now I get it.
I couldn't tell you the status, because the problem occurred some time ago and I unlocked it with pct unlock xxx.
The same evening, however, the backup ended regularly without any other problems.

If it happens again, I'll check the status.