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.
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).