Re: Memory Performance - When is RAM over committed ?

Kenneth,

Here is a simple method..

Keep a graph of the 1. CPU percentage and the 2. Interactive response time
on an ongoing basis. Add some throughput numbers if you can - say the number
of batch jobs each day, for example. You can definitely be fancy, and
measure it every hour, but really once or twice a day is good. Find some
common time/s of the day - say, 10:30am and 2:30pm where the load is high,
then collect and graph that data. All of these numbers should come from the
performance monitor, btw, and not from WRKACTJOB or WRKSYSSTS.

When you show this in graph format, use trending lines to see what is
happening and where it is heading. This will make it very clear what is
happening to the system visually, and will either support your argument, or
show you have 'plenty' of resources.

Once you get some pictures like this, you will be able to start trending
more and more values that suit your argument.

And, if you cannot prove your point, try some basic tuning principles to
increase throughput and balance the workload.

Good luck,
Trevor

P.S. Use PowerPoint to save green bar. The environment is already screwed
up.


On 7/20/09 11:44 AM, "Graap, Kenneth" <Kenneth.Graap@xxxxxxxxxxxxx> wrote:

Which performance measurement value(s) do you think would provide the
best evidence that memory (RAM) is beginning to be over committed on the
iSeries?

Do you think an analysis of faulting as a percentage of total disk
operations would provide a good objective measure of this, or would some
other measurement combination be better?

I would like to be able to provide objective evidence to upper
management that it is time to purchase additional memory... Even though
I know from experience that adding memory to the iSeries is ALWAYS a
good idea if throughput and/or response times start to increase...

Oh yes ... and please consider printing multiple copies of this e-mail
on green-bar paper.... <smile>

P
Please consider the environment before printing this email

Kenneth
Kenneth E. Graap
Systems Administrator
NW Natural
keg@xxxxxxxxxxxxx
503-226-4211 x5537