Memory intensive applications are not automatically disqualified, but need
to be looked at individually, and in terms of what the impact will be on the
rest of the systems/z/VM.  As Joe and Barton both recommend (and you say you
do), measurement is the only way to get a handle on whether a particular
piece of work will be a good candidate or not, and whether it will fit
within your existing capacity.

A particular CPU utilization on a RISC box is _likely_ to result in a higher
CPU utilization on the mainframe.  That's not guaranteed by any means, which
just reinforces the need to actually measure on both platforms.  Your
current practice of having people actually install their application on
Linux/390 and measure the results is absolutely the best way to go, in my
mind.  No guessing involved, real numbers gathered, etc.


Mark Post

-----Original Message-----
From: Eric Sammons [mailto:[EMAIL PROTECTED]
Sent: Friday, October 31, 2003 7:55 AM
To: [EMAIL PROTECTED]
Subject: Re: Perpetuating Myths about the zSeries


What about memory intensive?  And how do you gage the CPU intensive
applications?  For example we are planning to migrate some of our Solaris
(SPARC) applications off of SPARC and into the z/VM Linux world.  If I am
looking at candidates for this migration I see systems (SPARC) with 10 -
30 percent utilization.  What happens when I decide these word loads are
good candidates with their low cpu usage on the SPARC platform but then
install them into the Z environment and find out that they now have a cpu
usage of 80 - 90 percent?  Is this possible?  Is there a good way to judge
what applications on a given platform might be best suited for migration?
Right now I am recommending that any candidate first do a QA of their
application in the Z environment prior to do doing the full and final
migration.

thanks!
Eric Sammons
(804)697-3925
FRIT - Infrastructure Engineering





"Post, Mark K" <[EMAIL PROTECTED]>
Sent by: Linux on 390 Port <[EMAIL PROTECTED]>
10/30/2003 04:49 PM
Please respond to Linux on 390 Port

        To:     [EMAIL PROTECTED]
        cc:
        Subject:        Re: Perpetuating Myths about the zSeries

My answer was, and still is (and likely always will be) avoid any
application that is CPU intensive.  Yes, the zSeries has gotten faster,
but
so has Intel.  The price-performance curve for CPU intensive work still
favors Intel.  I've seen nothing in the IBM announcements that would lead
me
to change any of the recommendations I've been making for the last 3
years.
Unless and until the price-performance curve for zSeries matches that of
Intel (or comes a couple of orders of magnitude closer), I will continue
to
make the same recommendations.


Mark Post

-----Original Message-----
From: Jim Sibley [mailto:[EMAIL PROTECTED]
Sent: Wednesday, October 29, 2003 7:31 PM
To: [EMAIL PROTECTED]
Subject: Re: Perpetuating Myths about the zSeries


-snip-
Linux on all sorts of platforms was just a gleam in
someone's eye 5 years ago.  It started getting pushed
on the zSeries 3 years ago and the software and
hardware have made great strides in the last 3 years.

So CGI may not be appropriate today. So what is there
we said was not appropriate 2 or 3 years ago that may
be appropriate today on Linux zSeries?



=====
Jim Sibley
Implementor of Linux on zSeries in the beautiful Silicon Valley

"Computer are useless.They can only give answers." Pablo Picasso

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