Performance Tuning Suggestions for AS400

[Arthur Tyde]

Hello All,

My client has a totally bogged down AS400 running J.D. Edwards. We plan
to back up the entire system and do a restore to distribute data evenly
across three spindles to see if this helps. Other than cleaning up the
database- any suggestions on things we can do to make things run a bit
faster. Machine seems to be running interactive and batch jobs out of the
same queue- which has to stop. We have 80 users- run an average of 90% on
the CPU and have 256MB.

Would an additional memory board help? Currently running two CPU's with
room for four. According to the AS400 Performance Management book- a
third CPU adds a significant amount of processing power.

Anyone out there in the same boat with suggestions?!?

Many thanks, Arthur Tyde

[Rocky Marquiss]

There's a lot of things to check on in regards to performance. The
data is automatically spread throught the DASD so I don't see what you
will gain by your backup process - unless you plan on seperating the
disk drives into multiple ASP's and restore accordingly - but that can
lead into a bunch of nightmares all by itself. I personally think your
backup and restore will have much benefit for the time spent unless
you have gone through a WRKDSKSTS to see a particular drive getting
excessive hits and have identified what file(s) are the culprits. If
this is true, then save off those file(s), delete them and restore
them and they will spread out among the disk drives.

Interactive and Batch jobs definitely need to use different queues and
preferable different subsystems and most definitely need different
memory pools. Each priority ideally should have it's own memory pool -
priority 20 is *INTERACT, PTY 50 *SHRPOOL1, PTY 75 *SHRPOOL2, that
type of thing.

A third CPU can indeed add processing power, but you must be certain
that you are indeed CPU bound. If your problem is improper memory
utilization, the performance won't improve much or may even get worse
because of increased demand on the memory. I do not know what model of
AS/400 you are using, whether it is RISC or CISC. If it's a CISC
machine 256 MB should be plenty for 80 users, if it's RISC it may be
tight, but it doesn't give much leeway.

To do a "proper" job, one needs to run the performance monitor -
especially during the periods of worst performance - and analyze the
reports from them.

[Orangtang]

your question is a tough one to answer. There are so many factors that effect
performance. What you could try is running the performance monitor and
collecting data to see which programs are the "hogs". It could be the code,
SQL, OPNQRYF...etc....Your interactive jobs should not be runnnig out of the
same queue.. Are your memory pools set up properly? Check your page
faults...Ron

[Rocky Marquiss]

No misunderstanding here. Performance wise there is no "real" reason
to have interactive and batch in seperate queues. There are reasons to
have them the same. However, if it were me, I'd make a subsystem for
programmer signons and keep QPGMR as a batch subsystem, it has no
effect on performance as you point out.

Memory pool is indeed what is critical. Timeslice can effect it as
well, so classes can be important. What the maximum active jobs is
allowed in each memory pool - the setting of QPFRADJ system value, how
dynamic does the memory pool have to be(How much variation of the
workload between batch and interactive)? QPFRADJ has it's pluses - but
if your workload changes quickly, it's patheticly slow in keeping up,
even in V4R2 - albeit it's better than V3R2. How much of the CPU is
tied up with interactive verses batch? Are there jobs with different
prioirities? The list can go on and on.

Ideally, you have a seperate memory pool for each priority. One for
interactive of course (pty 20) and one for every batch priority.

On Sat, 29 Aug 1998 15:07:54 GMT, "Tim" <scot...@home.com.xyz>
wrote:

>Let me reply to a misunderstanding I am seeing here.
>
>Batch jobs and Interactive jobs can run safely out of the same job queue and
>therefore the same subsystem. They should not run in the same memory pool.
>
>For example in our shop we have a subsystem called QPGMR. This subsystem is
>for programmer sign-ons and batch jobs. The job queue QPGMR can be used for
>batch or interactive work. The routing data in this subsystem keeps the jobs
>separate. Jobs with routing data of QCMDI go to subsystem pool 2, All other
>jobs go to subsystem pool 3. Subsystem pool 2 is *INTERACT machine pool,
>Subsystem pool 3 is *SHRPOOL1 (reserved for batch work). Subsystem pool 1 is
>*BASE pool. (but our routing data never references it).
>
>
>
>
>
>
>
>Orangtang wrote in message
><199808290446...@ladder01.news.aol.com>...

[Kathy Loomis]

This sounds very interesting. Where do you suggest is the best place to go
to get more information on setting up subsystems and memory pools. The IBM
documentation we have is very confusing for newbies. Any help on this topic
would be greatly appreciated.

Kathy Loomis
Kat...@brzs.com

Tim wrote in message ...

[Mark Carbonaro]

You could possibly check out the IBM Redbooks they are better sometimes when
it comes to explaining things.

Kathy Loomis wrote in message ...