Hi Mike,

Mike Sun schrieb:
> For a research project, we've been doing a bit of hacking with Xen and
> utilize QCOW disk images as our VBDs. One intriguing thing about the
> QCOW2 format was support for multiple disk snapshots. Unfortunately,
> it seems from what I've been able to glean that support for multiple
> snapshots within a QCOW2 image is really only supported by QEMU's VM
> snapshot feature. Since I'm using Xen and only use QCOW2 disk images,
> I was wondering if there was any way from a tool such as 'qemu-img' to
> take snapshots of the QCOW2 disk image only and not through the
> general QEMU VM snapshot?

You can try the attached patch to qemu-img. I had it already for list,
delete and apply (as that's what I've needed so far), and I just added
create to it to make it complete. However, I didn't test it more than
making sure that it compiles and a new snapshot is listed afterwards.

If you're interested in having real snapshots with Xen, i.e. basically a
combination of xm save/restore and qemu-img snapshot, I also have some
patches to do that. They have quite a few dependencies, though, so they
are not yet upstream.

Kevin