I have a performance issue that I'm having trouble with - perhaps somebody has seen this sort of thing before and can help me out.
Problem: Under no load my page responses average about 1.2 seconds (according to jmeter tests), which is pretty good considering the heavy jdbc useage of my applications. However, once I begin to ramp up the load to 30 or 40 consecutive users the performance quickly degrades down to about 4 seconds average response time. While this takes place, the machines are only showing about 5% cpu utilization and have 3.5gb of memory freely available. Network resources also appear to be free. So I definitely don't have a hardware issue, especially considering that there are two balanced machines and neither are showing more than 5% busy. I seem to have a bottle neck somewhere in the system, but am unsure how to track it down. Setup background: This is a new setup that's not in production yet. I'm running Apache 2.05x and Tomcat 5.5x using mod_jk. Apache and Tomcat reside together on both machines (Win 2003), so there should be virtually no latency between them. The machines are balanced on the front end by Coyote Point Equalizers. Tomcat is handling connection pooling to our iSeries database server (db2, jdbc), but I'm not sure it's working correctly because when I do netstat I see several thousand db connections sitting at TIME_WAIT (presumably abandoned and waiting to be cleaned up by the pool manager). This could be one of my problems, but I don't think it's the whole problem and I don't know how to verify. The call to the pool manager is actually coming from the Spring Framework, which possibly has a bug in it, but I suspect instead that Tomcat is not returning the connections to the pool (unless I'm interpreting the existance of so many connections entirely wrong to begin with). I'm also using Tomcat to persist my sessions occasionally (every 2 minutes) to the same iSeries. I see several possible bottle neck points; the http forward from the load balancer to the server machine (very unlikely), the tcp communication between Tomcat and Apache (maybe), the jdbc connections to the iSeries (this is my top suspect at the moment) or some sort of db collusion occuring on the sessions persistance table. The big question: Anybody know a slick way to find out what it is? Thanks, -marc __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
