On 09/24/2013 01:02 AM, 王根意 wrote:

Hey guys:

I have a running vm with ceph backend:

root@apc20-005:~# virsh list Id Name State ---------------------------------- 56 one-240 running

And *snapshot-create-as* works well:

root@apc20-005:~# virsh snapshot-create-as one-240 Domain snapshot 1380009353 created

But when exec *snapshot-revert*, error occurs:

root@apc20-005:~# virsh snapshot-revert one-240 1380009353 *error: operation failed: Error -22 while loading VM state*

And the vm went paused state.

root@apc20-005:~# virsh list Id Name State ---------------------------------- 56 one-240 paused

When I use qcow2 image backend, Everything is ok! Any idea?

This happens because libvirt/qemu try to load the memory state of the vm, in addition to the disk state. RBD only saves the disk state, so attempting to load the memory state fails. There's a feature request for improving this [1]. You can revert the disk directly with the 'rbd rollback' command instead. Josh [1] http://tracker.ceph.com/issues/2773