Watch for the Domino 6.5 Redbook.  I had a chance to spend some
time researching and understanding performance of linux guests
under zvm and how to improve storage requirements.  The write up
will be in this redbook.  Last day of residency is tomorrow, so
would suspect redpiece in 60 days or so.

But to directly answer, working set sizes will drop with the
new apar. how much is yet an unknown, but it was the first
(or maybe second after timer patch) step that had to be
taken before we had the possibiltiy of understanding working
set requirements.  To me, a storage or a dasd problem is the
one I want to have.  For that there are tuning knobs and
tradeoffs.  It's the cpu problem that there's not a lot of tuning
for. Each application and workload will have different issues, but
i really think that storage is the best problem to have.

>On Thu, 28 Aug 2003, Mike Lovins wrote:
>
>>   Could someone help me out? we are in the process of purchasing a zSeries an
> plan on running Linux. I recieved this email about performance problems on the
> zSeries due to working set size, what is the working set size? and on what siz
> Zseries are having the problem?
>
>
>The term working set size relates to the amount of real storage your
>application needs. It might have, say, 128 Mbytes available to it, but
>actively use only a small part of it.
>
>Ironically, Linux can perform better in a small amount of virtual
>storage when run under VM: if it has 128 Mbytes it will tend to use it
>all for file bufferes.
>
>This impacts VM and can cause excessive VM paging. The solution can be
>to give it less storage, not more because this can reduce VM paging
>while not causing Linux to page much more.
>
>It's always the case that your milage will vary.







"If you can't measure it, I'm Just NOT interested!"(tm)

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