AS/400 - Single or dual (processor)?

We are again being courted by our friendly, neighborhood AS/400 dealer. We are currently on a 2 processor, 600 MHz machine, and the dealer is offering us a 1.6 GHz machine; the catch is that it is a single processor. Dual + processors are a quantum leap in price. Everything that we have read and been told says "the more processors, then better" when running OneWorld.

My question is whether anyone has moved from a dual processor to a single, and if so, how has your performance been impacted (+ or -)?

The new POWER5 processors are very powerful and really throw a kink int o
some of the old rules off thumb regarding number of processors. A 1-wa y
POWER5 box has close to the same CPW rating as an older 820-4-way. How ever
a lot of people are nervous moving to a 1-way because of processor
intensive batch jobs. So we tired to do some testing to compare
multiprocessor systems with a new 1-way box.

We did some comparison tests with an 820-4-way (3700 CPW) and a 1-way
POWER5 (3300 CPW) and the POWER5 box outperformed the 4-way. We ran 4
concurrent batch jobs on both, along with 250 test users. The user
response time was faster and the time it took for all UBEs to complete was
also faster. Even with 5 concurrent UBEs the POWER 5 completed all the
UBEs in about the same time and the users still showed faster response
time.

The new SMT (Symmetric Multi-Threading) really has an impact when you a re
running multiple workloads. The effect is to make a single processor l ook
like two processors. It won't have much effect for a single batch job, but
if you put multiple workloads...such as multiple batch streams and
users....then it will help.

We're in the process of putting together a whitepaper with the results. If
you're interested, I might be able to get a draft to you. Send me a no te.
otherwise, once it goes through all the reviews it will be posted at:
http://www-1.ibm.com/partnerworld/pwhome.nsf/weblook/pat_sol_peoplesoft .html

I realize this is a lab environment and you'll also want to hear about
"real-life" experiences from others on the list, but I wanted to make s ure
that you realize there is a difference between older 1-ways and the new
POWER5 chips....they really are a lot more powerful than earlier chips and
handle multiple workloads much better.

Good Luck!
Rob

Rob Jump
Sr IT Specialist
IBM/PeopleSoft International Competency Center
303-334-1054
[email protected]
http://www-1.ibm.com/partnerworld/pwhome.nsf/weblook/pat_sol_peoplesoft .html



RRobinson
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AS/400 - Single or dual
11/03/2004 05:52 (processor)?
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We are again being courted by our friendly, neighborhood AS/400 dealer. We
are currently on a 2 processor, 600 MHz machine, and the dealer is offe ring
us a 1.6 GHz machine; the catch is that it is a single processor. Dual +
processors are a quantum leap in price. Everything that we have read an d
been told says "the more processors, then better" when running OneWorld .

My question is whether anyone has moved from a dual processor to a sing le,
and if so, how has your performance been impacted (+ or -)?


RRobinson CPA/CITP,CNE OW Xe, SP22_X1, AS/400 V5R1, Update 8, Windows T SE
Big Ten JD Edwards Users Group Plymouth, Michigan, USA

RR -

600 total or 600 each? Either way you'll have 600 or 1.2 which is less than 1.6. Ask your dealer for the calculator provided by IBM. If I can find a link somewhere - I'll forward it.

AD

RRobinson,

DB2 Symmetric Multiprocessing on an AS/400 is licensed program - meaning just because you have two or more processors, doesn't mean you are using SMP.

Check your licensed programs and see if you have 5722SS1 Option 26 - this is DB2 Symmetric Multiprocessing for AS400.

If you don't even have SMP installed, I would definitely say that you should go for the new I5 (POWER 5) architecture.

Like you, I was a bit concerned about the potential switch from my 270 (dual 600 Mhz S-Star Class) to a 1.5 to 1.65 ghz uniprocessor I5 (which we didn't make...based on a lack of need). To sum up a TON of reading I finished a while back... AS400's really have been designed to be a true midrange box - uniprocessor doesn't need to be as scary as it would be on a wintel box. Even though IBM retired the CIW rating (compute intensive workload) as of the new architecture, I bet it would be a lot higher for the new processors - which is probably helping UBE's quite immensely.

For me, our UBE's currently run plenty fast - and we only run about 300 per day. Most of our AS/400 workloads are in SQL queries run outside of JDE (within custom apps we built to use JDE data). With that being said, IBM has stated that SQL performance for queries using the new SQL query engine for V5R2 and higher (as opposed to the CQE - classic query engine) can run TWICE as fast with DB2 SMP installed.

So, the next time I am allocated monies for AS/400 purposes, I expect I will get much more bang-for-the-buck by purchasing a $6,000 SMP license than a new server...

However, I would love to hear back from AS/400 users who went from a dual WITH SMP installed to a uniprocessor I5. What has been the effect on which workloads???