[PVE-User] Problem with QEMU drive-mirror after cancelling VM disk move

[Mikhail]

Hello,

On one of our clusters we're seeing issues with VM backup task - the
backup task fails with the following:

ERROR: Node 'drive-scsi0' is busy: block device is in use by block job:
mirror
INFO: aborting backup job
ERROR: Backup of VM 123 failed - Node 'drive-scsi0' is busy: block
device is in use by block job: mirror

I tried digging some information and it appears to be that there's
"drive-mirror" job in QEMU/KVM for this particular VM is blocking backup
process. It is clear to me that this problem started couple weeks ago
when we attempted to change VM's disk underlying storage, however the
"Move disk" operation was cancelled manually by administrator at the
time and backup tasks started failing right after that. I'm not sure
whether this is Proxmox issue or QEMU/KVM, but I suppose that stopping
and starting VM from within Proxmox will remove this block, however in
our case keeping this virtual machine up and running is critical and we
should avoid even 1-2 min downtime.

The question is how to remove this drive-mirror block online and how to
avoid this in the future.

# pveversion
pve-manager/6.1-7/13e58d5e (running kernel: 5.3.18-2-pve)

Thanks!
Mikhail.