Re: Advice regarding Disk Arm Utilization Spikes

If you are on V4R4 or later, check out the command STRASPBAL.

Here is an IBM link to try:
http://www-1.ibm.com/servers/eserver/iseries/whpapr/dasd_balance.html

Also, if you are member of Search400 (membership is free), go to this link
(one of the top 10 programmer tips):

http://search400.techtarget.com/tip/0,289483,sid3_gci793569,00.html




----- Original Message -----
From: <Mike.Crump@saint-gobain.com>
To: <midrange-l@midrange.com>
Sent: Monday, August 19, 2002 11:51 AM
Subject: Advice regarding Disk Arm Utilization Spikes


I have an intermittent problem whereas my disk arm utilization spikes
really badly.  Normally, we are in very good shape and at 15% or less.
However, on occasion (let's say 8-10 times a day and sometimes even none)
we will have for a minute and maybe two at most a spike on a number of
drives (6-12) for anywhere from 50% to 100%.  All the while my remaining
drives are coasting right along.

I've been running DBMON but have to admit I don't know what I'm looking at.
If I run it around the minute where the situation occurs I get a number of
hits on QSQSRVR jobs that are running for Websphere.  However, I can't tell
what file or index is in question.  If I list any field in the resulting
DBMON file that references file name or index name (name of table queried,
base table, index name, etc.) all I get is the value of NULL.

So, I'm pretty sure I have a 'hotspot' on a file(s) and that it is used
mainly in conjunction with WAS.  However, I have no idea of what.  And the
one minute time frame along with the intermittent nature is making the
STRASPBAL *USAGE attempts pretty worthless.

Right now, my only option seems to be to take the system down, backup the
complete library, remove the library, STRASPBAL, restore the library, and
STRASPBAL.  The WAS application hits over 50 files so I could subset it a
little but if I'm going to do that doing the entire library seems to be
worthwhile.

Any advice on how else to narrow down the file or use the STRDBMON results
that I am currently looking at?


Michael Crump
Saint-Gobain Containers
1509 S. Macedonia Ave.
Muncie, IN  47302
(765)741-7696
(765)741-7012 f
(800)428-8642

mailto:mike.crump@saint-gobain.com




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