在tomcat的catalina.sh中设置-server

Question

I am using Apache Tomcat 7.0.30 & JDK 1.7.0_71

I have set -server JVM argument in tomcat's catalina.sh

JAVA_OPTS="$JAVA_OPTS -Xms4096M -Xmx6144M -XX:PermSize=512M -XX:MaxPermSize=512M -server"
JAVA_OPTS="$JAVA_OPTS -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.port=14888"

How to check if tomcat is running in server mode ?

Can I check it using Visual VM ? By connecting to that tomcat using JMX port ? If yes, then where exactly it will be visible in Visual VM ?

Answer 1

You have -Xms4096M in your JAVA_OPTS . That will only work if you have a 64-bit JVM. IFAIK, 64-bit Java VMs run exclusively in server-mode. So, I think you're in server mode with or without -server , here.

To check the server mode under VisualVM, look on the "Overview" tab once you've connected to the remote JVM. Under the "JVM" heading, it will tell you what's running. For example:

JVM: Java HotSpot(TM) 64-Bit Server VM (25.45-b02, mixed mode)

That's a "server" JVM running, there.

Additionally, you should be using CATALINA_OPTS instead of JAVA_OPTS for that huge heap. Otherwise, you need a 4GiB heap just to launch the "tomcat stop" command.