Re: ASM and disk partitions offset

From: Radoulov, Dimitre <cichomitiko_at_gmail.com>
Date: Tue, 14 Feb 2012 00:08:45 +0100
Message-ID: <4F3997FD.4040005_at_gmail.com>



On 14/02/2012 00:00, Riyaj Shamsudeen wrote:
> I don't recollect exact details, but disk VTOC (Volume Table of
> Contents) information is kept in the initial part of the disk, in
> Solaris. You have to skip 1MB, so that VTOC is not overwritten. This
> applies only to Solaris, AFAIK.

Hi Riyaj,
thanks for pointing this out.

Yes, now I remember that I wasn't able to make the partitions visible for asm disk creation until I partitioned the disks using a non-default offset.
This requirement is documented in the Install guide for Solaris:

         Oracle Solaris fdisk partitions must start at cylinder 1, not cylinder 0.

Best regards
Dimitre

> Cheers
>
> Riyaj Shamsudeen
> Principal DBA,
> Ora!nternals - http://www.orainternals.com - Specialists in
> Performance, RAC and EBS
> Blog: http://orainternals.wordpress.com
> OakTable member http://www.oaktable.com and Oracle ACE Director
>
> Co-author of the books: Expert Oracle Practices
> <http://tinyurl.com/book-expert-oracle-practices/>, Pro Oracle
> SQL,Expert PL/SQL Practices
> <http://tinyurl.com/book-expert-plsql-practices>
>
>
>
>
> On Mon, Feb 13, 2012 at 4:31 PM, Radoulov, Dimitre
> <cichomitiko_at_gmail.com <mailto:cichomitiko_at_gmail.com>> wrote:
>
> Hi all,
> target environment:
>
> 11.2.0.3 RAC on RHEL 5.7 x86-64
> SAN HP 3PAR
>
> I'm reading the following note on MOS: RAC and Oracle Clusterware Best
> Practices and Starter Kit (Linux) [ID 811306.1],
> in the attached document RACGuides_Rac11gR2OnLinux.pdf is a step
> by step
> description of the GI and RAC installation process.
>
> Does anyone know what's the reason for the requirement for 1 MB offset
> for the first sector
> and if this requirement is valid on certain types of storage only?
>
>
> 3.1.1. Partition the Shared Disks:
>
> 1. Once the LUNs have been presented from the SAN to ALL servers
> in the
> cluster, partition the LUNs from
> one node only, run fdisk to create a single whole-disk partition with
> exactly 1 MB offset on each LUN to be
> used as ASM Disk.
>
>
>
> Thanks
> Dimitre
>
>
>
> --
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>
>
>

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Received on Mon Feb 13 2012 - 17:08:45 CST

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