I would like to have backup feature without the guest knowing about it. It should be no downtime and the backup should be able to be done on a guest running a busy mysql database or similar. I have come to a conclution that this may only be possible with lvm, but maybe its possible with kvm/qemu also.
Lets say I want to make a backup of a database running inside a guest. I don't want the guest to provide me with functionality about making this backup. All should be done with the help of virtualization and the fact that a guest hard drive is located on a server.
qemu monitor has a snapshot feature that can make this happen. Turning on the snapshot functonality and the base image will be static and it will be possible to make a exact copy of this image. I can then do whatever I want with this snapshot. Like mounting it in another guest to make backups.
So, how can I make a snapshot of a guest precise in time without the guest knowing about it?