Yoav, Would you be interested in working on a contract basis to assist us with this problem? If so what would your per hour charge be?
Thanks, Sam On Thu, 14 Oct 2004 16:06:37 -0400, Shapira, Yoav <[EMAIL PROTECTED]> wrote: > > Hi, > Excellent post, that one from Matt Dale -- good advice. > > Yoav Shapira http://www.yoavshapira.com > > > > > >-----Original Message----- > >From: Dale, Matt [mailto:[EMAIL PROTECTED] > >Sent: Thursday, October 14, 2004 4:04 PM > >To: Tomcat Users List; Sam Gallant > >Subject: RE: Tomcat 5 pause (free gmail account for fix :-) > > > >I reckon this still might be a garbage collection problem. > > > >I would download jvmstat from sun and use visualgc to monitor this. It > >gives a good graphical representation of when the box is garbage > collecting > >and how much stuff is in each of the generations. > > > >We had a similar situation and this arose because the app created lots > of > >very short lived objects. Increasing the young generation size > alleviated > >this problem and also reducing tenuring so medium term objects made it > to > >the old generation. > > > >There are also a few more garbage collection parameters you can play > with. > >If you have multiple processors you could try enabling the parallel > >collector. There is also the Concurrent Mark Sweep collector which > locks > >the JVM only in a small part of it's collection. You could try using > the > >aggressive heap settings which will try to use all the memory in the > >machine that it can. > > > >I think more visibility of your garbage collection cycles is the first > port > >of call in any event. > > > >-----Original Message----- > >From: Sam Gallant [mailto:[EMAIL PROTECTED] > >Sent: 14 October 2004 20:17 > >To: [EMAIL PROTECTED] > >Subject: Tomcat 5 pause (free gmail account for fix :-) > > > > > >Everyone, > >Thanks in advance for any help. Also I have a gmail invite for the > >person who has a fix for this if they are interested. > > > >My company has been using Tomcat for several years, but a problem has > >crept up that we have not been able to solve. Basically, tomcat will > >stop processing requests for 2-60 second period several times a day. > > > >Here is a list of software that we have tried. (Note we have tried > >changing each key componant to see if we isolate the componant that is > >the problem, but no luck yet) > > > >OS: RedHat 9 & AS3 > >Threading model: linux threads & nptl > >JVM: sun 1.4.2_4 & latest ibm > >Http connector: ajp w/apache 2 and coyote connector > >JBDC connector 1.0 > > > > > >1. Doesn't always happen durning old gen garbage collection, but does > >sometimes > >2. Before switching to incremental gc we received out of memory errors > >which resulted in Tomcat completly hanging > >3. After switching to incremental gc the effect changed to 2-60 second > >periods of time that Tomcat won't process request, but it does resume > >on its' own. > >4. Cpu usage for most of the day is less than 20% utiliztion, but when > >the problem occurs the cpu spikes to 100% utiliztion briefly. > > > >--------------------------------------------------------------------- > >To unsubscribe, e-mail: [EMAIL PROTECTED] > >For additional commands, e-mail: [EMAIL PROTECTED] > > > This e-mail, including any attachments, is a confidential business communication, > and may contain information that is confidential, proprietary and/or privileged. > This e-mail is intended only for the individual(s) to whom it is addressed, and may > not be saved, copied, printed, disclosed or used by anyone else. If you are not > the(an) intended recipient, please immediately delete this e-mail from your computer > system and notify the sender. Thank you. > > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
