PBS Backup Failed

[Jianming]

Dear All

ERROR: VM 110 qmp command 'backup' failed - backup connect failed: command error: unable to create owner file "/mnt/ddev/vm/110/owner" - File exists (os error 17)
INFO: aborting backup job
INFO: resuming VM again
ERROR: Backup of VM 110 failed - VM 110 qmp command 'backup' failed - backup connect failed: command error: unable to create owner file "/mnt/ddev/vm/110/owner" - File exists (os error 17)
INFO: Failed at 2026-05-20 10:25:07
INFO: Backup job finished with errors
INFO: notified via target `mail-to-root`
TASK ERROR: job errors

when i remove the "owner" file and run backup
ERROR: VM 118 qmp command 'backup' failed - backup connect failed: command error: unable to read "/mnt/ddev/vm/118/owner" - No such file or directory (os error 2)
INFO: aborting backup job
INFO: resuming VM again
ERROR: Backup of VM 118 failed - VM 118 qmp command 'backup' failed - backup connect failed: command error: unable to read "/mnt/ddev/vm/118/owner" - No such file or directory (os error 2)
INFO: Failed at 2026-05-20 10:56:27
INFO: Backup job finished with errors
INFO: notified via target `mail-to-root`
TASK ERROR: job errors


who can explain. What is the function of this "owner" file? If the backup is successful, will PBS delete this file? If not, then will this file's contents be cleared?

sometimes backup successfully, sometimes backup failed. the errors are the first error, which states that the file already exists.
I don't know what this means?
PBS mount is NFS.
IP:/data/col1/pbs /mnt/ddev nfs hard,intr,nolock,nfsvers=3,tcp,rsize=1048600,wsize=1048600 0 0
the NFS come from Dell DD.

datastore.conf add "--tuning gc-atime-safety-check=0" Because there is a conflict between PBS's GC and DD, this parameter is added.

thanks everyone

 

[Chris]

Hi,

please post the output of proxmox-backup-manager version --verbose. There were some changes in the past with empty group cleanup.

who can explain. What is the function of this "owner" file? If the backup is successful, will PBS delete this file? If not, then will this file's contents be cleared?

The owner file stores ownership information for a backup group, thereby controlling access and permissions. It is normally auto-created when the group is newly created and cleaned up when the group or the last snapshot within it gets destroyed. You should not need to manually add/remove the file.

sometimes backup successfully, sometimes backup failed. the errors are the first error, which states that the file already exists.
I don't know what this means?

Most likely you do have empty backup groups where the file has not been cleaned up as expected in the past. Make sure to manually clear such empty groups and try again. But first make sure you are running an up to date version.

datastore.conf add "--tuning gc-atime-safety-check=0" Because there is a conflict between PBS's GC and DD, this parameter is added.

I would strongly advice against disabling the atime safety check! The Dell Datadomain unfortunately is known to be incompatilbe with PBS, as it does not update the access time as expected, therefore you risk running into data loss when running garbage collection!

 

[Jianming]

Hello Chris




Most likely you do have empty backup groups where the file has not been cleaned up as expected in the past. Make sure to manually clear such empty groups and try again. But first make sure you are running an up to date version.

all of the vm groups are not empty group. such as below picture.



thanks

 

[Chris]

Then this is most likely yet another quirk of the Dell Data domain, PBS only tries to create the owner file if it does not exist already. And from your logs it would appear to be reported as such. But independent from this as already stated above, this storage boxes have known incompatibility with features required by PBS to work properly, see https://forum.proxmox.com/threads/missing-chunks-again.174295/post-811338 and https://forum.proxmox.com/threads/round-3-pbs-vs-dell-data-domain.175445/