[Full backups] Supports [NOBAK]

[julien-f]

It should be possible to exclude disks just like for delta backups.

Requirements:

• custom snapshot to avoid snapshotting the unwanted disk (save space)
• export using the delta format (no more XVA)

[olivierlambert]

Problem is: there is no way to ask XenServer to make a "partial VM snapshot" and therefore a partial export.

The only solution would be to manage doing it VM export manually (like in delta). But we'll lose the XVA format in the end (and compression on XenServer level).

[julien-f]

Or we could simply remove the VDI snapshot (or temporary the VBD) before the export like we do for delta.

[olivierlambert]

And what about the quiesce?

[julien-f]

It does not interfere with the quiesce because we delete the VDI on the snapshotted VM directly, after the snapshot process itself.

[olivierlambert]

Ah yes, so good idea then :)

[julien-f]

But it might interfere with the rolling snapshots feature, that why it could makes sense to simply remove the VBD before the export starts and re-creating it right after.

[tombresson]

This feature would be handy for me. I have a couple VMs I’d like to backup where a mounted disk doesn’t need backing up. Thanks for the solid work, guys!

[olivierlambert]

Hi @tombresson

It's tricky to do that in the most "clean" way, because it's on the frontier between XO and XenServer. Ideally, it should be XenServer work to be able to do so. That would be better because we could avoid to make a snapshot on a NOBAK disk, instead of doing it then removing it just after.

Maybe we'll do that in XCP-ng and maybe it will be merged in XenServer, I don't know yet.

[akurzawa]

+1 that would be great feature.
But how about OS? If a VM have two disk, and 2nd is connected to OS, what will happen during backup? the OS could break, because as I understand the disk will be physically disconnected from VM - I mean {Windows}.

[olivierlambert]

No, we disconnect the snapshot disk, not the active disk.

[julien-f]

For now, the implementation will be the same one than for delta backups: right after the snapshot, the disk will be removed from the snapshot.

[NormHenderson]

I think this merits attention. I have several production VMs with attached SR's that are far too large to snapshot. At present I have to shut them down, detach the SR, snapshot, reattach the SR, and reboot. I'm sure there are many others with the same requirement. Is it perhaps possible to quiesce/pause the VM, force detach, snapshot, reattach, and then resume? If so that would seem safe and relatively easy.

[olivierlambert]

This might be done relatively soon, in fact. At least, we can provide it in a dedicated release channel for a bit so people can test it :)