Open Stack

> 
> With respect to Cinder snapshots, there tends to be varying debates on
> this.  Thread [1] is from the last time we hashed this out on the ML.
>  Since then we've implemented a number of things in Cinder:
> 1. Clone (create duplicate volume, which for some uses a snapshot as an
> intermediate step in their implementation)
> 2. Backup (*real* long term durable backups that are independent of a
> snapshot currently sent to Swift)
> 
> And I have revert in the new LVM driver code that maybe I'll actually get
> back to finishing and submitting this week :)
> 
> A point of contention for a number of folks is that currently the base
> implementation is such that the snapshot is dependent on the source volume,
> but not all back-ends require this.  

To be fair, each snapshot-type has its use-case.

Isn't the whole point of snapshot is a point in time to quickly revert to a known sane
state, so depending on source is okay, I believe.

Maybe what you mean is a "clone".

> Some would like to see us make this
> behavior optional, but my argument has always been that I'd prefer to have
> the consistency around what a snapshot is rather than allow every back-end
> to implement something different.
> 
>>From my viewpoint, if you want a true clone or backup, then create a true
> clone or backup.

'true' for some definitions :)
> 
> Not sure if this helps or not, but hopefully it may clear up some of your
> questions about Cinder Snapshots.

Certainly, it gave more context into your thoughts.

Thanks John, for your response.

> 
> [1] http://www.gossamer-threads.com/lists/openstack/dev/21105



-- 
/kashyap