Re: RedHat 6 RAC Specific Questions & Concerns

  • From: Andy Colvin <acolvin@xxxxxxxxxxx>
  • To: development@xxxxxxxxxxxxxxxxx
  • Date: Thu, 22 Aug 2013 22:27:15 -0500

I've used MOS note #1062983.1 when recreating my ASM diskgroups - I haven't 
used it lately, but found it to be pretty reliable in the past (11.2.0.2 days). 
 It covers the difference between 11.2.0.1 (crsctl start crs -excl) and 
11.2.0.2+ (crsctl start crs -excl -nocrs), and gives the commands to recreate 
your CRS diskgroup, create a new generic spfile, and get the cluster back up 
and running.
I strongly recommend creating a separate ASM diskgroup for your OCR and voting 
disks for one reason in particular.  On most platforms running RAC/ASM, you 
will be using external redundancy.  When creating OCR/voting disks in ASM on 
11.2, the redundancy level of the diskgroup determines how many voting disks 
are created.  External redundancy gets 1 voting disk, normal redundancy gets 3, 
high redundancy gets 5.  It's generally a good idea to build out a small high 
redundancy diskgroup of 5 LUNs to provide the best protection.  The loss of 
that LUN in external redundancy will take the node down.  Losing one LUN in a 
high redundancy diskgroup will not affect the cluster at all.

Andy Colvin

Principal Consultant
Enkitec
andy.colvin@xxxxxxxxxxx
http://blog.oracle-ninja.com



On Aug 20, 2013, at 2:34 AM, Martin Bach <development@xxxxxxxxxxxxxxxxx> wrote:

> Hi Jeremy,
> this is an interesting thread. When you have a moment would you compare 
> your notes against mine? Admittedly I didn't have to recreate the ASM 
> instance
> 
> http://martincarstenbach.wordpress.com/2011/10/13/the-tale-of-restoring-the-ocr-and-voting-files-on-linux-for-rac-11-2-0-2/
> 
> Your comment about an ASM spfile backup is noted :) I have spent a 
> little time yesterday with spget/spcopy in asmcmd and agree that there 
> are some quirks with it. I believe a possible solution would be to use 
> spbackup regularly in cron or similar to back the ASM spfile up. If you 
> ever have to restore you use spcopy with the -u flag to update the gpnp 
> profile. I found a few notes yesterday that explains the spfile/pfile 
> steps-it's 1082943.1.
> 
> Martin
> --
> Martin Bach
> Enkitec (The Exadata Experts)
> http://www.enkitec.com
> http://martincarstenbach.wordpress.com
> 
> 
> --
> //www.freelists.org/webpage/oracle-l
> 
> 


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