[Qemu-discuss] backup procedure validation

[Raphael Bauduin]

Hi,

I found out qem-nbd can mount a snapshot, but this feature is not much documented or discussed (or I didn't find the good resources), so I'd like to have some confirmation before I use it for my backups.
Here is the sequence of actions I would take:
 stop domain
 qemu-nbd --connect /dev/nbd0 --read-only --snapshot /path/to/file.qcow2
 start domain
 mount /dev/nbd0p1 /mnt/src
 rsync -a /mnt/src /mnt/dest
 umount /mnt/src
 qemu-nbd --disconnect /dev/nbd0

With these actions, can I be sure that
- my backup of the filesystem is correct and coherent  ?
- the domain can continue to work normally despite the nbd snapshot ?
- when the nbd is disconnected, its snapshot is removed ?

Thanks

Raphaël