PBS backups of the PBS root disk stopped working

[dpearceFL]

I have a three node PVE 8.3.4 cluster. PBS is running as a VM on one node. Up until last week, it was backing up the PBS VM successfully for many weeks in a row via snapshots. I can certainly understand while the backup would fail as it is trying to freeze the VM while it is being snapshotted, but why was it working and it just suddenly stopped?

The PBS 3.3.3 VM has two disks on it: One for the root drive and one for the data. The latter is excluded from the backups.

Here are the logs from the failed backup:

INFO: starting new backup job: vzdump 100 --mode snapshot --notification-mode auto --notes-template '{{guestname}}' --remove 0 --storage PBS --node csswx-virt2
INFO: Starting Backup of VM 100 (qemu)
INFO: Backup started at 2025-03-10 13:05:39
INFO: status = running
INFO: VM Name: BackupServer
INFO: include disk 'scsi0' 'TrueNAS:100/vm-100-disk-0.qcow2' 32G
INFO: exclude disk 'scsi1' 'TrueNAS:100/vm-100-disk-1.qcow2' (backup=no)
INFO: exclude disk 'scsi2' 'TrueNAS:100/vm-100-disk-2.qcow2' (backup=no)
INFO: backup mode: snapshot
INFO: ionice priority: 7
INFO: creating Proxmox Backup Server archive 'vm/100/2025-03-10T17:05:39Z'
INFO: issuing guest-agent 'fs-freeze' command
INFO: issuing guest-agent 'fs-thaw' command
ERROR: VM 100 qmp command 'backup' failed - backup connect failed: command error: http request timed out
INFO: aborting backup job
INFO: resuming VM again
ERROR: Backup of VM 100 failed - VM 100 qmp command 'backup' failed - backup connect failed: command error: http request timed out
INFO: Failed at 2025-03-10 13:07:40
INFO: Backup job finished with errors
TASK ERROR: job errors

Is the best answer to have another PBS VM built to only backup the one VM to the same datastore?

 

[dpearceFL]

Unless I get a better answer, I did create a second PBS server to backup the main PBS root disk and this works.

 

[Chris]

Self referencing backups are not a good idea, I would recommend to backup the PBS VM using the regular VMA backups to a completely different storage so you can restore it without issues in case disaster strikes.

The PBS 3.3.3 VM has two disks on it: One for the root drive and one for the data. The latter is excluded from the backups.

Do you have remote sync jobs configured or how do you plan to restore this in case your TrueNAS storage is not available anymore?

INFO: issuing guest-agent 'fs-freeze' command INFO: issuing guest-agent 'fs-thaw' command ERROR: VM 100 qmp command 'backup' failed - backup connect failed: command error: http request timed out

I can only guess here, but maybe the fs-freeze and fs-thaw took a bit longer now than the did previously, leading to the http request timeout. Anyways, self referencing backups are not a good idea.