Re: ASM disk groups

EMC is recommending a min. of 2 disk groups so that you can balance I/O's across two Logical Volumes (Metas in your DMX). This way you will stripe at the ASM level and at the host level as well and you'll end up with a double stripe. Here is my 2 cents on ASM disk group recommendation if you can afford the disks.

ASM diskgroup 1 - 2 LUNs - for Datafile and Indexes
ASM diskgroup 2 - 2 LUNs - for Redo logs
ASM diskgroup 3 - 2 LUNs - for Archive logs

Raj

On 3/7/06, K Gopalakrishnan <kaygopal_at_gmail.com> wrote:
>
> Tim:
>
> ASM uses SAME methodology internally and your data is striped and
> mirrored across ALL avaiable disks. So I donot understand why would
> you need a traditional split. If you need more redundancy, you can go
> for triple mirroring from ASM or other mirroring at EMC level.
>
>
> If you are worried about the meta data failures,corruptions.. I have
> not seen any. But FYI, ASM Metadata also triple mirrored !
>
> KG
>
>
> On 3/7/06, Tim Onions <att755_at_hotmail.com> wrote:
> > Dear All
> >
> > Management have committed to getting a new EMC DMX3 top of the range
> SAN. We
> > will be running a Linux RHEL4 10gR2 RAC database against it. We are some
> > months away from go live so have lots of testing and such to do. However
> EMC
> > are asking for the disk layout detalis now, and reading Oracle/EMC docs
> they
> > say all we need is 2 ASM disk groups. The trouble is one will be 1.2Tband
> > contain all our datafiles (system, temp UNDO included) and that don't
> feel
> > right. Changes to the EMC configuration will be expensive and impact
> other
> > SAN usage if done later on.
> >
> > Does anyone have any practical experience on ASM on a SAN and are thus
> able
> > to comment on whether Oracle docs are right in saying place all this
> data in
> > a single disk group? Any good reasons for not opting for a more
> traditional
> > split?
> >
> > TIA
> >
> > Tim Onions
> >
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>
> --
> Best Regards,
> K Gopalakrishnan
> Co-Author: Oracle Wait Interface, Oracle Press 2004
> http://www.amazon.com/exec/obidos/tg/detail/-/007222729X/
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