RE: Oracle 10g RAC on AIX 5.3

I just finished an implementation of 10.2.0.3 RAC on AIX 5.3, having done many Linux and Solaris versions before.  

OCFS / OCFS2 is only available for Linux and Windows. For AIX, GPFS or possibly Veritas Cluster File System would be the way to go (I am not positive that VCS is available for AIX). However, both are costly- we decided purely on cost to go with ASM.  

For ASM , you have the database and (optional) flash recovery area on the SAN (which is presented as raw devices to ASM), and the Oracle home on local disks (one home each for every RAC node). You also present raw devices for the OCR and Voting disk- they are small (200mb or less) but due to storage system limitations you might have a minimum size requirement for a device. Our storage systems have a 1gb minimum size for each LUN, and I have heard of up to 8gb for other systems, but each is different.  

ASM is actually easier to implement than I thought- you don't need to worry about sharing, mounting etc. You just have your storage guy or Unix sysadmin present the devices to the host, make sure the permissions are correct for the Oracle user, and that the devices map correctly (for example, /dev/rhdisk1 MUST be /dev/rhdisk1 on each and every node). This is actually a subset of the tasks that they would have gone through for a filesystem anyhow. Having separate Oracle homes makes patching a bit more flexible, since you can do rolling upgrades which cannot be done with a shared Oracle home. Not every patch is eligible for rolling upgrades, but the patchsets generally are.  

Backups must be done with RMAN: if you are still doing old-style hotbackups at the filesystem level, then be prepared to abandon that method. But if you are using RMAN then everything is covered. Both Exports and Datapump can be used but you need to write to a filesystem.  

Your direct question was: So the question, do we need OCFS, or GPFS, or neither, or both?? The answer is Neither, or GPFS / VCS, depending on what you want to do. The only drawback is that storage presented to ASM can only be used by ASM.  

For AIX on RAC, there are a number of OS modules required, and most are detailed in the Oracle AIX manuals, but some are not- they become identified as prereqs for the other modules. The Cluster Verification Utility should point out what is missing. For instance, even in a non-HACMP setup, you still need a bunch of HACMP modules that are part of the base OS but not frequently installed.    

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Jason Heinrich Sent: Monday, December 10, 2007 2:48 PM
To: richard.goulet_at_capgemini.com
Cc: oracle-l_at_freelists.org
Subject: Re: Oracle 10g RAC on AIX 5.3  

Last I checked, Oracle does not provide OCFS for AIX, so if the client needs a clustered file system, GPFS would be the way to go. Whether or not they need it depends on what they want to do. You could install the Oracle software on each node and use ASM for the database storage. However, if you want a shared ORACLE_HOME or a shared non-ASM logging location, you'll need the clustered file system.

On 12/10/07, Goulet, Dick <richard.goulet_at_capgemini.com > wrote:

Guys & Gals,  

            I've done Oracle RAC install on Linux before, but noiw I'm being asked to do so on AIX 5.3 and I seem to be getting mixed signals from Oracle. The client originally wants to install AIX 5.3 with GPFS, but now to save a buck has decided not to install GPFS, but to instead use OCFS. On the other hand the Oracle docs are telling me that a clustered file system is only needed for the Oracle binaries. So the question, do we need OCFS, or GPFS, or neither, or both?? Anyone really know??    

-- 
Jason Heinrich 


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