On Tue, Jun 21, 2011 at 2:53 PM, Eric Blake <eblake@redhat.com> wrote:
On 06/21/2011 04:30 AM, Daniel P. Berrange wrote:
Upstream qemu is developing a 'live snapshot' feature, which allows the creation of a snapshot without the current downtime of several seconds required by the current 'savevm' monitor command, as well as means for controlling applications (libvirt) to request that qemu pause I/O to a particular disk, then externally perform a snapshot, then tell qemu to resume I/O (perhaps on a different file name or fd from the host, but with no change to the contents seen by the guest). Eventually, these changes will make it possible for libvirt to create fast snapshots of LVM partitions or btrfs files for guest disk images, as well as to
Actually, IIUC, the QEMU 'live snapshot' feature is only for special disk formats like qcow2, qed, etc.
Does anyone have pointers to the qemu implementation of monitor commands used for live snapshot?
http://repo.or.cz/w/qemu.git/blob/HEAD:/blockdev.c#l572 Jes implemented the snapshot_blkdev command and is integrating guest agent fsfreeze support. I think it needs to be a multi-step process instead of just one command so that libvirt can do storage management for LVM and co. Stefan