RE: Partition LUNs for Oracle ASM

-----Original Message-----
From: Radoulov, Dimitre [mailto:cichomitiko_at_gmail.com] Sent: Friday, January 25, 2013 1:21 PM
To: Walker, Jed S; oracle-l_at_freelists.org Subject: Re: Partition LUNs for Oracle ASM

On 25/01/2013 19:24, Walker, Jed S wrote:
> Thanks for the document reference. It looks pretty much like what is in the Documentation. It doesn't clearly state whether LUNs should be partitioned or not, but I get the impression you can use them as is.

Hi,
Oracle(r) Grid Infrastructure Installation Guide 11g Release 2 (11.2) for Linux E22489-08 states the following:

3.3.1.4.2 Configuring Disk Devices to Use Oracle ASM Library Driver on x86 Systems
To include devices in a disk group, you can specify either whole-drive device names or partition device names. [...]
Note: _Oracle recommends that you create a single whole-disk partition on each disk_.

The best practice document Rac11gR2OnLinux on MOS suggests to use asmlib and to partition the disks:

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.

Once I tried to use non-partitioned LUNs on Linux using multipath with device mapper and the installation went smoothly. It was just a quick test though, I don't have such a configuration in production.

That said, a very simple method to achieve partition alignment is to completely avoid partitioning (see http://www.fhgfs.com/wiki/wikka.php?wakka=PartitionAlignment).

Regards
Dimitre

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