Re: [Qemu-devel] [RFC PATCH 3/4] qmp: Add "snapshot=" option to nbd-server-add

[Paolo Bonzini]

Il 22/08/2013 10:53, Fam Zheng ha scritto:
>> > This is handy but only works if the QEMU process has permission to
>> > create temporary files.
>> > 
> Yes, this is a shortcut, it has this limitation, but the good side is
> it's easy to get and no other dependency.
> 
> To avoid creating file, we'll need blockdev-add to override backing_hd,
> and blockdev-backup to use an existing BDS as target, then we simply use
> current nbd-server-add to export it.
> 
> This series is still RFC, with above said, we still need to decide which
> is the way we (QEMU and libvirt) want for 1.7.  any thoughts?

I think this was the initial design, but Kevin already said he didn't
like the idea.

(Also, if you do this you have to add nbd-server-add to qmp-transaction,
to atomically start fleecing of multiple devices).

Paolo