Re: creative use of storage snapshots.
- From: Nuno Souto <dbvision@xxxxxxxxxxxx>
- To: oracle-l@xxxxxxxxxxxxx
- Date: Tue, 21 Dec 2010 22:58:24 +1100
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@xxxxxxxxxxxx
Niall Litchfield wrote,on my timestamp of 20/12/2010 11:07 PM:
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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