Re: creative use of storage snapshots.
Date: Tue, 21 Dec 2010 22:58:24 +1100
Message-ID: <4D109660.4080601_at_iinet.net.au>
Works like a charm, been doing it for nearly 2 years now with our DW.
Things to watch out for:
- the snapshot dbs are not full-on production ones, they have to be strictly for
development/testing purposes.
- if the gap between the snapshot and the original gets too big, the subsequent
resynchs can take quite a long time. Work on the basis of number of blocks
changed: the more, the slower the catch up will be.
There are a number of technologies that can reduce the overhead of the first copy of each changed block of the snapshot. Netapp has an interesting mechanism that reduces the overhead to a single write operation, EMC is more of a read/compare/write proposition.
Worth re-stating: no one runs production on a snapshot, so whichever technology you use don't expect miracles. Once the expectation is set right, the technology works like a charm and is eminently suitable to the "refresh/test" cycle of development environments. It makes all those refreshes a matter of minutes, rather than hours on end.
We're planning to expand this approach to all dbs: MSSQL and Oracle, once we finally decide on our new hardware platform. Coming up in a couple of months. We're expecting huge reductions in volume for multiple Peoplesoft HR, ERP and CRM environments, where everyone seems to need a copy of the entire database to test a single invoice...
-- Cheers Nuno Souto in sunny Sydney, Australia dbvision_at_iinet.net.au Niall Litchfield wrote,on my timestamp of 20/12/2010 11:07 PM:Received on Tue Dec 21 2010 - 05:58:24 CST
> Hi List
> I have a client with storage technology that allows copy on write snapshots to
> create a writeable copy of a storage volume. They are looking at potentially
> using this technology to provision clones of a DR database for
> development/testing and reporting purposes. The idea being that as these
> databases would be a) short lived and b) have limited changed data block volume
> going through them and c) not have high performance requirements they could save
> considerable amounts of storage by splitting off a clone using the snapshot
> technology rather than a conventional oracle based approach. I'm aware of
> Delphix Database virtualization which looks like it addresses similar issues in
> a similar way. Is anyone out there doing something similar - it sounds to me
> like one of those great ideas that have a huge gotcha that I can't think of
> right now.
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