Re: 11gR2 San Migration - OCR Disk Group

From: Andy Colvin <acolvin_at_enkitec.com>
Date: Fri, 6 Apr 2012 10:25:21 -0500
Message-Id: <E1CC4108-9EAE-44BE-B5F6-53DAEF765BA3_at_enkitec.com>



I haven't tried with the OCR component, but I don't see why it wouldn't work. I have checked the behavior WRT voting disks. Assuming that you have normal or high redundancy on your OCR/voting diskgroup, when one fail group containing a voting disk is lost and there is another fail group in the diskgroup that doesn't contain a voting disk, the missing voting disk will be created in that unused fail group. For example, if you have a diskgroup with 4 fail groups (FG1, FG2, FG3, and FG4) in normal redundancy, assume that voting disks are in FG1, FG2, and FG3. If fail group 3 was dropped, a voting disk will automatically be created in FG4. ASM will not wait for the disk_repair_time or a rebalance.

Here's the description from Oracle's documentation (http://goo.gl/SpCv5) - "If voting disks are stored on Oracle ASM with normal or high redundancy, and the storage hardware in one failure group suffers a failure, then if there is another disk available in a disk group in an unaffected failure group, Oracle ASM recovers the voting disk in the unaffected failure group."

Here's a post that I wrote about voting disk redundancy in ASM - http://blog.oracle-ninja.com/2012/01/voting-disk-redundancy-in-asm/

Andy Colvin

Principal Consultant
Enkitec
andy.colvin_at_enkitec.com
http://blog.oracle-ninja.com

On Apr 6, 2012, at 9:35 AM, Jeff Thomas wrote:

> Running 11.2.0.2.5 RAC on Linux x86. We are migrating to a new SAN.
> With respect to the OCR diskgroup, which is defined with 3 disks with
> normal redundancy, I do know how to migrate the OCR/voting files/ASM
> spfile to a new OCR diskgroup if need be.
> What I wonder if anyone has migrated the OCR diskgroup by simply adding the
> new disks and dropping the old ones? Is Oracle smart enough
> to copy the 3 voting files over to the new disks, so that's there no outage
> whatsoever when migrating to the new SAN?
>
> Best,
> Jeff
>
>
> --
> http://www.freelists.org/webpage/oracle-l
>
>

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Received on Fri Apr 06 2012 - 10:25:21 CDT

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