On 11/12/2012 03:58 AM, zhijun liu wrote: 'virsh save' saves _just_ memory state, and then shuts down the guest. If you alter the disks externally before restoring, you've hosed your guest. 'virsh snapshot' has more features. In fact, when libvirt 1.0.1 is released, 'virsh save $dom $file' will be shorthand for 'virsh snapshot-create-as --no-metadata $dom --memspec $file --diskspec vda,snapshot=no' for a guest with a single disk named vda. But right now, we're still working on getting all the corner cases right for that sort of usage. Yes, both commands can be used in VM backup; the list archives have several threads on these topics (it's a hot question lately). If you have more specific questions (and when I have more time than I had for this email), I'd be glad to provide more details. -- Eric Blake eblake(a)redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org