[pve-devel] some news for snapshots

[Dietmar Maurer]

> >>I mean I see the problem with backup, but external hnapshot has much
> >>more problems, because you need to do a merge after the backup?
> 
> Yes,we need to merge if we want to delete the snapshot after the backup.
> and now, this is from parent to children.

But this is simply not practical - copying the whole image is totally stupid!
 
> > By making the snapshot-file argument of the monitor and QMP command
> > optional, that could be used as a request to make the snapshot
> > internally instead of to an external file.
> 
> so this is using the blockdev-snapshot-sync without file argument to do
> snapshot internal, in the current qcow2.
> I talk with qemu mailing, this is not planned for now.
> 
> >> However, without live block migration of an
> > internal snapshot, there is no way to make a backup of an internal
> > snapshot while still leaving the VM running, so this feature is not
> > planned at the present. For now, the snapshot-file argument is
> > required, and only external snapshots are implemented.
> 
> Yes, indeed with external snapshot, we can backup the parent file.
> This is good for backup only I think.

No, we can't use external snapshot for backup, because the merge afterwards is simply not practical.