Re: AS/400 Performance

[mcrump@xxxxxxxxxxxxxx]

Performance Tools is one of the best ways.  This LP gives you a command that is
a little more informative than WRKACTJOB.  WRKSYSACT is a little less intensive
in that it will only show you truly active jobs, it is more intensive in that it
comes in at a lower priority, and it can be a little more representative of the
system because it will also show system tasks.  If you do not have Performance
Tools you will have to do something different.

Performance on the system will center on the CPU, memory, and disk.  Any three
(or combination thereof) can cause performance degradation.  WRKACTJOB is your
best bet on CPU (sort it on CPU %).  WRKSYSSTS is your best bet on memory.  The
work management guide is a good reference on fault rates (which is what you want
to look at).   WRKDSKSTS is the tool to look at your disk.  You are looking for
% Busy numbers that exceed certain thresholds.  I think the Work Management
guide has something on guidelines for this.  You will be concerned if you see
numbers that exceed maybe 40 or 50%.  Someone can help me here....my % busy
numbers are so low I never remember the thresholds.  Typically, it is the CPU %
that will show you the cause (overall high CPU% by interactive jobs, abusive
interactive jobs, etc.).

How do you have the system configured for QDYNPTYSCD and QPFRADJ set?  This may
or may not help.

There are differing opinions on performance collections.  There are those of us
who run it all the time and those that run it only when necessary.  I run it all
the time because we constantly report performance information to management.
The impact is typically estimated at 3-5% of your CPU.  If you have performance
tools you can run the collection for a day and then run some reports and graphs
to get some ideas.  This area is a whole discussion on it's own.

If you have no luck isolating and don't have performance tools you can still run
the data collection.  I would be willing to analyze your performance information
on one of my systems.  All you need to do is send it to me on tape.  If
interested you can contact me privately.

HTH

Mike Crump




Gary Munroe <GMUNROE@flemingc.on.ca> on 05/06/99 10:17:16 AM

Please respond to MIDRANGE-L@midrange.com

To:   midrange-l@midrange.com
cc:    (bcc: Mike Crump/IS/Ball-Foster)

Subject:  AS/400 Performance




What is the best way to find out how the system is performing (v3r2)?
We seem to be noticing slowdowns but cannot necessarily narrow down
the cause.  We look at WRKACTJOB to see who might be running an
intensive job but it doesn't always reflect the slowdown we feel.  I
know there is performance data collection but we are under the
impression it makes a big impact on the system by itself.  Are there
any general maintenance tips we should be following?  Also, does a
reclaim storage do a defrag to the disks?  What would?  Would this
help?

Thanks.


 __________________________________________________________________
| Gary Munroe                                                      |
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| I.T.S., AS/400 Services        Work: gmunroe@flemingc.on.ca      |
| Sir Sandford Fleming College   Home: izzi@calweb.com             |
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