Red Hat Bugzilla – Bug 739339
virsh snapshot-revert is not reverting the disk image
Last modified: 2012-01-04 14:11:18 EST
Description of problem:
1. Ceated a new domain using a qcow2 img file as the storage, installed F15 on it, shut it down.
2. Created a snaphshot using virsh snapshot-create
3. Started the domain and updated its packages, shut it down.
4. Created a 2nd snapshot.
When I run virsh snapshot-revert on the domain I get no output from virsh and it returns quickly. Nothing in /var/log/messages either. I start the domain and it has not reverted the disk.
virsh snapshot-list does list the snapshots.
If I use qemu-img it lists the disk snapshots and I am able to use qemu-img snapshot -a X to switch snapshots successfully.
This package has changed ownership in the Fedora Package Database. Reassigning to the new owner of this component.
This is a known issue, due to a change in qemu behavior, and fixed in libvirt version 0.9.5 and later. However, the fix is rather invasive, and I'm not sure it is feasible to backport the appropriate patch and all prerequisites into F15; at this point, I'd rather close this as fixed in F16 and suggest that you upgrade.
Author: Eric Blake <email@example.com>
Date: Fri Aug 26 16:17:41 2011 -0600
snapshot: properly revert qemu to offline snapshots
Commit 5e47785 broke reverts to offline system checkpoint snapshots
with older qemu, since there is no longer any code path to use
qemu -loadvm on next boot. Meanwhile, reverts to offline system
checkpoints have been broken for newer qemu, both before and
after that commit, since -loadvm no longer works to revert to
disk state without accompanying vm state. Fix both of these by
using qemu-img to revert disk state.