轉載自：http://readwall.blog.163.com/blog/static/1012713220106610347337/
這篇文章是對內存調整真正起作用的，
CATALINA_OPTS or JAVA_OPTS?
CATALINA_OPTS is used to control Tomcat environment options, whereas JAVA_OPTS controls the environment options at a higher level ie. for any Java library.
You can start Tomcat with more heap memory using the following:
On Windows
Edit the file $TOMCAT_HOME\bin\startup.bat and insert or alter the following line, substituting for the desired values:
set CATALINA_OPTS=-Xms(min heap)m -Xmx(max heap)m
For example if you want to allocate a minimum heap size of 256MB and a max heap size of 512MB you will have to write the following on Windows:
set CATALINA_OPTS=-Xms256m -Xmx512m
The line you add should go just before the line starting call “%EXECUTABLE%”…
If you are running tomcat 5.5 via tomcat.exe, you can update the heap size by running tomcatw.exe and setting the required values via the Java tab.
On Linux
Edit the file $TOMCAT_HOME/bin/startup.sh and insert the following line, substituting for the desired value, eg. Bash Shell:
export CATALINA_OPTS=”-Xms(min heap)m -Xmx(max heap)m”
The line you add should go just before the line starting exec “$PRGDIR…
Permanent Generation Size
If you get the error message: java.lang.OutOfMemoryError: PermGen space you need to add the argument -XX:MaxPermSize=128m to CATALINA_OPTS, in addition to any argument you use to set the heap size.