RE: Why separate pools?

["Ingvaldson, Scott" <SIngvaldson@xxxxxxxxxxxx>]

OK, I'll have to add my 2¢.  

1.)   To change the minimum and maximum pool sizes go to WRKSHRPOOL and do
F11.  

2.)   When adjusting for performance the answer is always "it depends."
There are a few rules.  You should keep batch work out of interactive
subsystems.  IBM has also always recommended separating batch work from
base.  Beyond that you can try to keep like work grouped together, depending
on your memory constraints.

I would start with 5 pools, *MACHINE, *BASE, *INTERACT, *SPOOL and
*SHRPOOL1.  Put all of your batch jobs in *SHRPOOL1.  If you have something
like 11 Domino partitions running and you have gobs of memory let them have
their own pool.  You can let that pool have a good sized minimum memory;
your Domino servers will start quickly and QPFRADJ will do the rest.  

Another potential reason for an additional pool is to "pin" a file to
memory.  You can set a private pool with enough memory to hold the entire
file and a job or jobs can access it without paging. (SETOBJACC Command)

http://www-912.ibm.com/s_dir/slkbase.nsf/3cdf5d853ca698198625680b00020369/dc
0a2297bdaefddb86256d6c0069907f?OpenDocument&Highlight=0,pin,memory

Time slices can control some things, but do you want an interactive job to
have to wait for a batch job to complete its (comparatively long) time slice
before it can run?  Make all of these changes slowly and pay close attention
to the results.

Regards,
 
Scott Ingvaldson
iSeries System Administrator
GuideOne Insurance Group

-----Original Message-----
date: Tue, 23 Nov 2004 11:32:13 -0500
from: rob@xxxxxxxxx
subject: Re: Why separate pools?

Where is the "minimum" set?

Rob Berendt
-- 
Group Dekko Services, LLC
------------------------------
date: Tue, 23 Nov 2004 12:05:11 -0500
from: rob@xxxxxxxxx
subject: Re: Why separate pools?

Now it's getting to the point where I really need to digest this 
information

My interpretation of what you said is that when one pool pages, it only 
pages pages out of it's memory pool.  For example, if interactive pages 
out a few pages, it won't affect the pages of memory that a set of jobs in 
batch might be using and successfully sharing a file.  Right?
Do people like SSA or Software Plus actually write applications to take 
advantage of this?
Wouldn't the separate memory pools inhibit applications in batch from 
sharing memory pages containing data that interactive jobs might be able 
to use?

Doesn't QPFRADJ, and it's genre, alter activity levels also?  Could that 
mean that I am tying up CPU for one pool that might be better used in 
another?  If I am dynamically changing the activity levels, why not lump 
them all together and get a faster leveling out?

Time slices could still be controlled by subsystem, thus giving different 
time slices to batch vs. interactive.  Having them in a separate pool is 
not required to have different time slices.


Rob Berendt
-- 
Group Dekko Services, LLC
   
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