[libvirt] snapshots and LVM

[Chris Lalancette]

On 05/11/2010 02:01 PM, Daniel Berteaud wrote:
> Le mardi 11 mai 2010 à 13:39 -0400, Chris Lalancette a écrit :
>>
>> It's certainly something that would be nice to see.  I even have FIXME
>> comments in the code about supporting LVM snapshots; I just haven't had
>> time to take any look at it.  If you have time/interest, I'd be happy to
>> review patches doing it!
> 
> I saw your comments in the snapshot code, I was just waiting for
> snapshot merging to be available to start talking about LVM snapshot
> support (because, without merging, snapshots are not very useful ;))

Well, it does support merging, to a degree, though it's an implicit
feature in the way the other snapshot mechanisms work.  That is, if you
do something like:

Base Image -> snap1 -> snap2 -> snap3

And now delete snap2, the changes from snap2 are automatically merged
into snap3 to keep snap3 a viable snapshot.

I think we'll have to explicitly do this for LVM (though I'm not sure;
my experience with LVM snapshotting is 0).

Besides this implicit merging action, do you want/need the ability to
manually merge snapshots?  What's your use-case, so I can understand
it better?

-- 
Chris Lalancette