Increasing Tomcat Heap Size

Question

I'm trying to increase the heap size of tomcat (so i can optimize GeoServer performance), what i did is:

• Change the JAVA_OPTS values in tomcat default file to be:

JAVA_OPTS="-Djava.awt.headless=true –Xmx3072m -XX:MaxPermSize=512m"

• Restart tomcat

When I checked JVM values is shows:

Free memory: 440.33 MB Total memory: 495.06 MB Max memory: 2969.62 MB

I'm not sure whether this good or not.

Answer 1

-Xmx will set the maximum heap size. The the JVM will allocate more memory as needed up to that limit. If you, for some reason, want to allocate more memory for the heap at JVM start, use the -Xms option in addition to the -Xmx option.

See the Oracle docs for details.

Also, these options refer to RAM, so the HD space is not relevant.