I don't know how helpful this is.... But we do run F5 loadbalancers in front of our biggest app. There are 2 servers hitting us every 5 seconds each for HTTP and for 2 for HTTPS. So, a total 4 hits every 5 seconds. But it runs across 17 z9 EC IFL's and there's never an idle time so I couldn't really tell you exactly how much CPU that accounted for but ... Very rough math here ... We get about 130 TPS at 60% busy so 2 TPS is about 1% busy. 1% of 17 IFL = .17 IFL or 17% of an IFL. If the trans were full blown -- but you said they are not the full blown trans...
Can you take your interval from 2 seconds to a higher number and see what happens? (and yes, they are fat cpu intensive trans in case anyone wonders :) You can also check in your HTTP logs how often they really do hit you. 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: Linux on 390 Port [mailto:[EMAIL PROTECTED] On Behalf Of Kate Riggsby Sent: Monday, September 10, 2007 10:21 AM To: [email protected] Subject: [LINUX-390] linux performance behind load balancer Greetings, As part of our linux proof-of-concept project we built a new instance of the servers which provide our big student services application. The application runs on Oracle Web Application Server. The zlinux instance is running pretty much alone on a z/800 ifl and has oodles of real memory. The application only accepts work from 7am to midnight; the rest of the time it responds to any queries by putting up a page listing the hours of availablity. The linux userid running the application was using about 3-4% of the cpu. The day we added our instance to the (external) load balancer its base cpu consumption went to 18% of the ifl, even during application downtime. It does seem to be able to do its share of the work by using an additional 15% of the cpu when the application is open, but we are puzzled that the polls by the load balancer seem to eat so much of a z/800 ifl. The participating standalone (Dell) boxes get polled too but run at <1% during downtime. Our IBM business partner is helping us investigate, but I thought I'd ask this forum of experienced users if you've seen/conquered performance problems running behind load balancers, or have an opinion about how much work will fit on a z/800? I have been told that the load-balancer polls are an xchange of Hello/Server Hello packets on port 443 (not a full-blown SSL handshake) every 2 seconds. thanks, kate Kate Riggsby University of Tennessee ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
