Tomcat: The Definitive Guide

Chapter 4. Tomcat Performance Tuning

Once you have Tomcat up and running, you will likely want to do some performance tuning so that it serves requests more efficiently on your box. In this chapter, we give you some ideas for performance tuning the underlying Java runtime and the Tomcat server itself.

The art of tuning a server is complex. It consists of measuring, understanding, changing, and measuring again. The basic steps in tuning are:

1. Decide what needs to be measured.

2. Decide how to measure.

3. Measure.

4. Understand the implications of what you learned.

5. Tinker with the configuration in ways that are expected to improve the measurements.

6. Measure and compare with previous measurements.

7. Go back to step 4.

Note that, as shown, there is no “exit from loop” clause. This is perhaps representative of real life, but in practice you will need to set a threshold below which minor changes are insignificant enough that you can get on with the rest of your life. You can stop adjusting and measuring when you believe you’re close enough to the response times that satisfy your requirements.

To decide what to tune for better performance, you should do something like the following:

1. Set up your Tomcat as it will be in your production environment. Try to use the same hardware, OS, database, etc. The closer it is to the production environment, the closer you’ll be to finding the bottlenecks that you’ll experience in your production setup.

2. On a separate machine, install and configure the software that you will ...