On 19/11/2014 13:07, Prof. Dr. Michael Schefczyk wrote: > Yes! My level of knowledge is that one uses the qcow2 format in order > to be able to create live snapshots/backups. Otherwise one would tend > to use the more efficient raw format. Is this not correct and did I > apply the backup mechanism in the wrong way?
That's correct, but you still have to create live snapshots from within QEMU. This is done with a QMP (QEMU Management Protocol) command like { "execute": "blockdev-snapshot-internal-sync", "arguments": { "device": "ide-hd0", "name": "snapshot0" } } QMP is accessed through normal sockets, or via libvirt. However, I'm not sure if running "qemu-img convert" on the resulting snapshot is possible though, and there is no equivalent of "qemu-img snapshot -d". You can instead use QEMU's support for backup, which will do what you wanted directly while the VM is running. For example: { "execute": "drive-backup", "arguments": { "device": "ide-hd0", "sync": "full", "format": "qcow2", "target": "backup.img" } } This does not even require qcow2 for the image. The downside is that you must not turn off the VM until the job has completed. Paolo