[pve-devel] ZFSPlugin snapshot question

[Dietmar Maurer]

> Yes, I will look in to this this weekend.
> 
> Forgot to mention. Since snapshots by nature is read-only you have to
> set option wp=true to have iscsi properly advertise read-only to the
> mount util. I think Linux will make some internal optimization given it
> knows writes is not supported.

Just thought a bit more about that, and maybe we can handle this
by just creating a clone?

I just committed some changes for the current LXC snapshot backup code:

https://git.proxmox.com/?p=pve-container.git;a=commitdiff;h=4ca61ce824c9f5cc46c938e01d82f985eeac1f67

It works like this:

1.) create snapshot
# pct snapshot <VMID> vzdump

2.) mount snapshots read-only

3.) create tar archive

4.) destroy snapshot
# pct delsnapshot <VMID> vzdump

This only works if we have read-only access to storage snapshots,
which is a problem with the current ZFSPlugin.

Another approach would be:

1.) create a clone
2.) backup cloned VM with 'stop' mode

That way we do not even need to implement 'snapshot' backups ;-)

Any comments about that idea?