How many processors are you running on? We started with one IFL, and WebSphere & HTTP don't play well in a uniprocessor environment. We started to have intolerable levels of CPU wait at about 70% utilization. The second processor made a world of difference.
Richard Heritage Lead Systems Software Engineer IT @ Johns Hopkins >>> Marcy Cortes <[EMAIL PROTECTED]> 10/25/06 6:45 PM >>> It does depend :). We have a WAS application, running on multiple SuSE instances as well, also talking to DB2 on z/OS and using MQSeries. It has very strict response time requirements. If it can't do all of its stuff and respond to the client (the ATM systems) within 2 seconds, those other systems "standin" and give the customer the money anyway (based on some rules). At somewhere near 80% here queues build up causing more cycles to be used process them, etc. and standins to occur and folks pagers to start vibrating. I once ran something on another virtual machine at very low priority (share relative 10) thinking I could as someone said, mop up some of those extra cycles... Wrong!! Marcy Cortes "This message may contain confidential and/or privileged information. If you are not the addressee or authorized to receive this for the addressee, you must not use, copy, disclose, or take any action based on this message or any information herein. If you have received this message in error, please advise the sender immediately by reply e-mail and delete this message. Thank you for your cooperation." -----Original Message----- From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On Behalf Of Richard Heritage Sent: Wednesday, October 25, 2006 9:30 AM To: IBMVM@LISTSERV.UARK.EDU Subject: [IBMVM] CPU Utilization Limit I know this is an "it depends" question, but I hope some of you can give me a very general answer. As an MVS guy, I'm used to being able to run the processor very close to or even at 100% without significant performance degradation. Assuming that everything is configured and tuned properly (a big assumption, I know), can VM drive the processor the same way? Our application people are used to other platforms that don't tolerate high CPU utilization so well and think things are going to start falling apart when we hit 80%. I'd like to reassure them--but only if it's accurate to do so! This is a WebSphere application running on multiple SUSE instances, with the data on DB2 under z/OS. Is it reasonable for me to expect--again, assuming everything else is right--to be able to run at 90+ percent without problems? Richard Heritage Lead Systems Software Engineer IT @ Johns Hopkins
