I'd suggest that you try the following JVM options in your Tomcat JAVA_OPTS environment variable (before deploying these changes in production, test these options in an isolated environment with stress testing tools if at all possible):
JAVA_OPTS= -Xms1024m -Xmx1024m -verbose:gc -server - By making -Xms and -Xmx the same, you will minimize CPU cycles spent on growing the block of memory allocated to the Tomcat JVM by the OS. If you have more memory available, use it for Tomcat, so long as you allow sufficient "headroom" for other services you may be running, as well as the OS itself. Test to determine how high you can safely go with these parms. - The -verbose:gc option will output statistics to the Tomcat console that will tell you the "before" and "after" memory stats behind JVM garbage collection operations. Use the "after" number to determine approximately how much RAM the Tomcat JVM is consuming at a given moment. Much of the time, the JVM does not use all the memory shown by the Windows Task Manager as being in use. - As I understand it, the -server option is generally recommended when using Tomcat in a server environment. That aside, buy enough (>=2G) RAM so that you can take advantage of a larger memory allocation. Win 2K permits a total of 4G per process; 2G of that is mapped to the OS kernel leaving 2G for your app. If you only have 1G or so installed, you're missing an opportunity for an inexpensive way to increase performance and decrease downtime and hair loss! Hope this helps. Cheers, Gordon Smith -----Original Message----- From: Marco Aurélio Seraphim da Silva [mailto:[EMAIL PROTECTED] Sent: Monday, June 26, 2006 11:09 AM To: users@tomcat.apache.org Subject: Out of Memory Error Hi folks, I'm using Tomcat 5.0.28 with JVM 1.4.2 (running only Tomcat) under a Win 2000 Server, and it starts to give me the following message: java.lang.OutOfMemoryError. To prevent this I start Tomcat using this 2 parameters: -Xms 521m -Xmx 1024m But this isn't enought, some times when the server is a bit stressed the server memory, used by the JVM incrises up to 1GB and some MB more, then decrises to 700MB, and starts to increse again up to 1GB. The memory used increses just as the app sessions, but when the JVM used memory get at 1GB I have at about 400 sessions. I'm thinking that is to much memory for 400 sessions on this app. I'm afraind becuse the memory get up to 1GB when the server is not full stressed. There's something I can do to reduce the amount of memory used by the JVM, or it's normal??? Thanks, Marco Aurélio Silva --------------------------------------------------------------------- To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] --------------------------------------------------------------------- To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
