You will need to be able to check the following things:
portal.log
The portal.log will be loacated in the directory that was your current directory from which you started your JVM. Otherwise you can configure /properties/Logger.properties to place it in a specific place.
catalina.out
This file is located in the logs directory under Tomcat's install directory.
web server request log
garbage collection log
You will need to set some setting to enable the garbage collection log in your JVM. The following is the setting is what we used for Java 1.4.1.
export CATALINA_OPTS="-Xms256m -Xmx512m -Xloggc:/usr/local/tomcat4/logs/tomcat_gc.log"
thread dump of the jvm
On Linux you can use the following to create a thread dump of all the running Java threads.
The thread dump will be written to Tomcat's catalina.out file.
This little script assumes you have only one process called java.
#force the JVM to do a stack dump to stdout which ends up in catalina.out PID=`ps -AH | pgrep java |head -n 1` kill -3 $PID
On Windows you can hit CTRL-BREAK in Tomcat's console window to get a thread dump.
cpu usage
On Linux you can look at the load average and the CPU percent used using the top command.
If these are high Don't Panic and test how long it takes to load up a page in uPortal.
network connections
memory usage reported by the OS
Memory usage reported by the OS can be misleading when running Java. Don't Panic and you'll want to pay more attention to the garbage collection log than to the memory reported by the OS.
Tips:
Leave debug information compiled in. In our performance tests (at Texas Tech University) we found that removing debug information only increased performance by a small factor, yet having the line number information helped diagnose problems (even performance problems) much more quickly.
Set the LogLevel to INFO. The debug info is too verbose for production. In production you should be looking at error level and exceptions most of the time.
Allow Apache to serve up static content like images and html.
Tune your SQL indexes.