There have been recommendations to never use VxFS for TSM Database and
Storage Volumes posted on this list that I never quite understood.  However,
I am suspecting that the issue has to do with setting up VxFS correctly,
similar to the file system maxperm issues on AIX.  I am not sure how JFS and
VxFS were compared here.  It would have had to been different hardware which
throws a wrinkle in the results.  Until just a few months ago VxFS was not
available for AIX.  More often than not, it is the way the file systems are
setup and the hardware they are on versus one or the other so long as they
have the similar features of JFS and VxFS.  This is based on my testing of
XFS on IRIX, JFS on AIX, and VxFS on Solaris all on the same disk subsystem,
an IBM ESS all fibre channel connected.

Paul D. Seay, Jr.
Technical Specialist
Naptheon Inc.
757-688-8180


-----Original Message-----
From: Bob Booth - UIUC [mailto:booth AT UIUC DOT EDU]
Sent: Saturday, September 21, 2002 3:34 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: RAW volumes or not


I have used both on AIX, and really have never seen a difference either way.

I use LVM raw volumes for both, since I find them easier to deal with.  TSM
mirrors the database/log volumes, and AIX mirrors the storage pool volumes.

TSM V5 can utilize AIO for JFS under with AIX, and this is a different ball-
game altogether.  I am not actually sure if JFS is native on Solaris, you
have to have Veritas installed, and this will render a significant
improvment over the native Solaris filesystem I/O.  Check with your sources
to see if they are indeed running Veritas on their Sun systems.  I have
compared VXFS and AIX JFS on machines of the same performance
characteristics, and they perform about the same (under various tests VXFS
did beat JFS, I used IOZONE).

Seeing arguments either way, I use raw LV's for ease of configuation and
smaller overhead (no jfslog, etc).

good luck.

bob

On Sat, Sep 21, 2002 at 07:03:38PM -0000, Arni Snorri Eggertsson wrote:
> Hiya,
>
> I've been reading about using RAW volumes for database and diskpool
> volumes, my impression is that when running AIX and using JFS the
> benefits are trivial. However I've seen people talking about 200-300%
> performance increase when running TSM on Solaris.
>
> What I am wondering is if anyone has actually done experiments with
> this on AIX on a real environment, i.e. performance check using JFS on
> one hand and then RAW volumes on the other?
>
>
>
> thanks,
> Arni Snorri Eggertsson
> arnie AT gormur DOT com