Owner check failed, even if all backups deleted beforehand

[kwinz]

Hi,

so far I did backups as a different user.

Now I deleted all old backups, and garbage collected the old backups.
According to the GUI the Proxmox backup server (PBS) is completely empty.

However if I attempt to do backups as the new user, I am getting errors like:

INFO: creating Proxmox Backup Server archive 'vm/109/2023-03-11T12:10:24Z'
ERROR: VM 109 qmp command 'backup' failed - backup connect failed: command error: backup owner check failed (pve-user@pbs != olduser@pam)
INFO: aborting backup job
INFO: resuming VM again
ERROR: Backup of VM 109 failed - VM 109 qmp command 'backup' failed - backup connect failed: command error: backup owner check failed (pve-user@pbs != olduser@pam)

I know the forum is full of suggestions to simply change the owner for each VM's backup with proxmox-backup-client change-owner vm/109 [...]. I tested this command on one of the affected VMs and it resolved the issue.

But I actually want to understand why this error occurs at all.
If I can't see the VM's backups in the Datastore any more, and they have been garbage collected, why and where does PVS still keep track of the old owner?

Thanks in advance!

PS: It's not just the GUI that shows that the delted vm/109 backups are gone, also root@proxback01:~# proxmox-backup-client list --repository Backup01 doesn't list any VM 109 backups that supposedly still have the old owner. Is there a CLI command that will show vm/109 and which owner PVS thinks those backups have? How do I show the owners on the CLI?

 

[fiona]

Hi,
while I didn't design this, I think it makes sense that as long as the group exists, it has an owner. Otherwise, somebody else (with backup access to the datastore) could "steal" the group and become the new owner.

The owner is stored in a file in the top level of the backup group:

root@pbs1 /mnt/datastore/bigone # ls host/pve701
owner

If you delete the whole group rather than all backups in the group, the owner file will be gone too.

The UI does not show empty groups.