Open Stack

On Sat, Sep 26, 2015 at 12:02 PM, John Spray <jspray at redhat.com> wrote:
> On Sat, Sep 26, 2015 at 1:27 AM, Ben Swartzlander <ben at swartzlander.org> wrote:
>> All snapshots are read-only... The question is whether you can take a
>> snapshot and clone it into something that's writable. We're looking at
>> allowing for different kinds of snapshot semantics in Manila for Mitaka.
>> Even if there's no create-share-from-snapshot functionality a readable
>> snapshot is still useful and something we'd like to enable.
>
> Enabling creation of snapshots is pretty trivial, the slightly more
> interesting part will be accessing them.  CephFS doesn't provide a
> rollback mechanism, so

Oops, missed a bit.

Looking again at the level of support for snapshots in Manila's
current API, it seems like we may not be in such bad shape anyway.
Yes, the cloning case is what I'm thinking about when talk about
writable shapshots: currently clone from snapshot is probably going to
look like a "cp -r", unfortunately.  However, if someone could ask for
a read-only clone, then we would be able to give them direct access to
the snapshot itself.  Haven't fully looked into the snapshot handling
in Manila so let me know if any of this doesn't make sense.

John