[pve-devel] VM snapshot problem

Dietmar Maurer dietmar at proxmox.com
Fri Aug 24 13:15:41 CEST 2012

> >>Why not? I thought one can specify that with the qmp command?
> oh maybe for qcow2 can we use the original file as target ?

If not possible, we need to implement that ourselves.

> -> { "execute": "blockdev-snapshot-sync", "arguments": { "device":
> -> "ide-hd0",
>                                                          "snapshot-file":
>                                                         "/some/place/my-image",
>                                                         "format": "qcow2" } }
> >>I still think we should use internal snapshots. That live merge/commit
> >>proposal sound like a bad idea to me.
> Yes, seem difficult to maintain.
> Also for rollback, we need use on the snapshot file in the qemu command
> line file=...
> >>I just though we can use external snapshots when there is no other way
> >>to do it.
> >>We can even disable 'remove snapshot' support for that case (simply do
> >>not allow to remove intermediate snapshots)?
> I don't know. When you do a snapshot, the new datas are written in the
> snapshot file.
> So,I think we need to merge it if we remove the snapshot. (removing the
> snapshot is merging it)

Ah, I see. The whole thing gets really clumsy with external snaphots. So I guess
we should start with internal snapshots only.

> Internal snapshot is more easy, as datas are in the file, we only need to
> "qemu-img snasphot -d" to remove the snapshot.


> But it is possible online with qmp?

I had no time to test that. But qmp need to support that for rdb and sheepdog anyways?

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