Backup fails when (additional) container disk is on ZFS ZVOL

[yummiweb]

Proxmox VE 9.1.4
Proxmox Backup Server 4.10

(The problem did not occur under PVE 8 / PBS 3)

Object: Container
Disk 0: "root"
Disk 1: "mp0" (/mnt/db_backups)
Disk locations: ZFS ZVOL

Problem:
Backup to PBS fails with the following error:

ERROR: Backup of VM 164001 failed - command 'mount -o ro -t zfs ZFS_POOL/zvol/subvol-164001-disk-1@vzdump /mnt/vzsnap0//mnt/db_backups' failed: exit code 2

(Note the double "/" in the path after vzsnap0)

Details:

vzdump 164001 --mode snapshot --storage PBS_LOCAL --remove 0 --notes-template '{{guestname}}' --node base16 --notification-mode notification-system
INFO: Starting Backup of VM 164001 (lxc)
INFO: status = running
INFO: CT Name: admv1
INFO: including mount point rootfs ('/') in backup
INFO: including mount point mp0 ('/mnt/db_backups') in backup
INFO: backup mode: snapshot
INFO: ionice priority: 7
INFO: suspend vm to make snapshot
INFO: create storage snapshot 'vzdump'
INFO: resume vm
INFO: guest is online again after <1 seconds
ERROR: Backup of VM 164001 failed - command 'mount -o ro -t zfs ZFS_POOL/zvol/subvol-164001-disk-1@vzdump /mnt/vzsnap0//mnt/db_backups' Failed: Exit code 2

In the end, an undeleted snapshot "vzsnap" of the container remains.

Current workaround:

I moved "mp0" (/mnt/db_backups) from ZVOL to the file-based area of ZFS_POOL – the backup works from there for now.

regards Yummiweb

 

[Impact]

Please share pct config 164001.

from ZVOL

Can you elaborate on this? Why/how did you use a ZVOL?