RE: We've Added more memory...but I can't remember!

> > If it does, any GENERAL rule of thumb to follow for incrementing the
> > MACHINE pool?

Rick  --

I disagree with Andy on a couple of points.  First, unless IBM has made some
major architectural changes that I don't know about, the VAT (virtual
address translator) mechanism requires some pinned memory in the machine
pool to keep track of what "real" address is stored in each memory frame.
If I remember correctly - when you add 16 gigabytes of memory to a system
you need to put 1 gigabyte of additional memory in the machine pool just for
that purpose alone.  The rule of thumb is one sixteenth of the memory added
needs to be added to the machine pool.

Second, the "guidelines" for acceptable faulting are totally bogus.  It is
not "OK" to have hundreds of non-database faults per second.  Every fault
requires something to be brought from the disks into memory.  These poor
disks are busy enough (don't get me started on the disk problem.)  If you
have a performance problem you can either keep buying hardware until the
performance improves enough, or you can take action to reduce the
unnecessary faulting.

--  Charly


>From: "Andy Nolen-Parkhouse" <aparkhouse@attbi.com>
>
>Rick,
>
>Yes, if you do not have performance adjustment turned on, then all
>additional memory will go to *base.  No, you don't need to make the
>machine pool bigger because you've added additional memory.  Best bet
>would be to examine the faulting rates in your various pools, including
>the machine pool.  The work management manual will provide guidelines
>for acceptable levels depending on the power of the machine.  Only older
>manuals are available in any depth, perhaps there is something in
>InfoCenter.
>
>If you have oodles of memory now, why not just turn on the automatic
>adjustment and see where the pools settle.  The auto tuning works much
>better than it did in the older releases and might just make your life
>easier and your users happier.
>
>Regards,
>Andy Nolen-Parkhouse
>
> > On Behalf Of Rick Rayburn
> > Subject: We've Added more memory...but I can't remember!
> >
> > ...if I need to "goose" up the machine pool with additional "wattage".
> >
> > the memory was added because we got a great deal on the chips NOT
>because
> > we
> > were experiencing problems. I believe all of the additional "K" was
>dumped
> > into *BASE but I'm not certain.
> > Does anyone remember/know if memory additions ALWAYS dump into Base?
> > If it does, any GENERAL rule of thumb to follow for incrementing the
> > MACHINE
> > pool? I believe I OVER-allocated memory to the "SPOOL POOL" by
>granting an
> > average of 300 K per active writer. Any thoughts on that as well...or
> > anything else memory-pool related?
> >
> > Thanks all.
> >
> > Rick Rayburn
>


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"We are still waiting..."  -  Alan Cox in 2002

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Charly Jones
253 265-6244
Gig Harbor
Washington USA



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