[libvirt] Error saving/restoring VM with attached disks

[Shi Jin]

Hi there,

I have been playing with libvirt/KVM on saving the VM to a checkpoint file and restoring it from this file. It has worked very well for me on my RHEL-5.5 setup, until I added hot-plugged volumes.

If I add a volume to a running VM using "virsh attach-disk" and then call "virsh save". The checkpoint file was successfully written and VM stopped.
However, I get errors restoring it with "virsh restore":
$ virsh restore checkpoint 
error: Failed to restore domain from checkpoint
error: operation failed: failed to start VM

I did two thinngs to narrow down the problem:
1. If  I manually remove the lines of attached volume from the checkpoint file, then it restores fine.
2. If I have the additioinal volumes in the original XML template instead of hot-plugging them on the fly, the save/restore work very well.

So I think the problem is in save/restore hot-plugged volumes.
Do you think this is a bug or an expected behaviour?
Should I file a bug report? Any fix already?

Thank you very much.
Shi

--
Shi Jin, PhD