Re: [libvirt-users] Live Snapshot and Rebasing using blockpull

Eric, Thanks for the clarification. I will wait for a backport of qemu 1.1 for Ubuntu 12.04 so I can use the safer 'transaction' monitor command for performing live snapshots/backups. Is there any other recommended method for live backups? Andrew ----- Original Message ----- From: "Eric Blake" <eblake(a)redhat.com&gt; To: "Andrew Martin" <amartin(a)xes-inc.com&gt; Cc: libvirt-users(a)redhat.com Sent: Friday, August 17, 2012 9:43:23 AM Subject: Re: [libvirt-users] Live Snapshot and Rebasing using blockpull On 08/17/2012 08:27 AM, Andrew Martin wrote: Yep. As long as you don't mind the single image changing names, this works (and if you _do_ mind it changing names, you can do the process twice to get back to the original name, although that's obviously not very efficient). There are future improvements coming down the pipeline for even more efficient block manipulations, but they missed the qemu 1.2 cutoff, so now I have to wait for qemu 1.3 (probably closer to December of this year) before having libvirt control over those features - but I am actively working on this area of code. snapshot-create-as was introduced in libvirt 0.9.5, and requires the qemu 'blockdev-snapshot-sync' monitor command (since 0.14.0), but prefers the 'transaction' monitor command (since 1.1) for safety. blockpull was introduced in libvirt 0.9.4, and requires the qemu 'block-stream' monitor command (since 1.1). It sounds like you can take snapshots but not merge them back while your domain is online, because your qemu is too old. But you can use 'qemu-img' to do offline merging, if having your domain offline is not an issue. -- Eric Blake eblake(a)redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org