Any Memory Usage Limitation for Tomcat 5 or 6?

[Ashik Uzzaman]

Is their any built in memory usage limitation for Tomcat 5? For example, we can add a JAVA_OPTS and specify -Xms and -Xmx to tell the JVM the maximum memory space that can be used. But if I have 8 GB RAM in my server and I tell Xms to be 4 GB and Xmx to be 8 GB to Tomcat 5, will it be able to utilize 8 GB memory if required? Is there a limitation around it for Tomcat 5 (like maximum 2 GB will be used)? And for Tomcat 6? I tried to find the answer in tomcat documentation without success.

Your comments will be appreciated.

[Marco Ehrentreich]

Hi Ashik,

the amount of memory Tomcat can use mainly depends on the JVM and OS. If you want to use multiple GBs of RAM you will have to use a 64 bit OS/JVM. Then you can set the catalina options for Tomcat to higher values than the default for 32 bit JVMs (which is depending on the OS ~ 1,5 GB).

Marco

[Kees Jan Koster]

For more detail of the limitations of 32-bit systems, and a graphic of how the memory is laid out: http://java-monitor.com/forum/showthread.php?t=570

Kees Jan

[Misha Ver]

Ashik, keep in mind that a larger heap will cause garbage collection pauses to increase because there is more heap to scan