virsh blockjob $domain --abort

[Peter Krempa]

On Tue, Nov 30, 2021 at 08:15:30 +0200, Jeff Brown wrote:
> Please advise:
> 
> After a scheduled crontab snapshot backup of a VM it failed to do a
> blockcommit, and is currently writing to both the snapshot and the original
> QCOW2 images.
> 
> (I don't think it's a bug, and suspect that I caused it by running the
> backup script manually while the snapshot was already running.)
> 
> $ virsh blockcommit VM sda --active --pivot --shallow --verbose
> error: block copy still active: disk 'sda' already in active block job

The '--pivot' switch here ...

> 
> $ virsh blockjob VM sda --info
> Active Block Commit: [100 %]
> 
> $ virsh domblkerror VM
> No errors found
> 
> Running on Debian 9 (Stretch).
> 
> $ virsh version
> Compiled against library: libvirt 3.0.0
> Using library: libvirt 3.0.0
> Using API: QEMU 3.0.0
> Running hypervisor: QEMU 2.8.1

(this is a rather old libvirt version, but what I suggest below should
work)

> 
> Now, I've read up on the probable solution, somewhat, but running $ virsh
> blockjob $domain --abort on this production server scares me; and I'm just
> asking whether it would be advisable to stop services and make a full data
> backup prior to doing so? It would entail taking the services offline for at
> least an hour. The snapshot is currently at 12GB,  and according to blockjob
> --info the VM image is 100% in synch.

... is equivalent to do a 'virsh blockjob $VM $DISK --pivot' after the
blockjob is complete. In your case, the original virsh invocation was
probably killed or missed the finishing event and thus didn't finalize
the blockjob.