Tomcat: The Definitive Guide, 2nd Edition

Capacity Planning

Capacity planning is another important part of tuning the performance of your Tomcat server in production. Regardless of how much configuration file-tuning and testing you do, it won't really help if you don't have the hardware and bandwidth your site needs to serve the volume of traffic you are expecting.

Here's a loose definition of capacity planning as it fits into the context of this section: capacity planning is the activity of estimating the necessary computer hardware, operating system, and bandwidth necessary for a web site by studying and/or estimating the total network traffic a site will have to handle, deciding on acceptable service characteristics, and finding appropriate hardware and operating systems that meet or exceed the server software's requirements to meet the service requirements. In this case, the server software includes Tomcat, as well as any third-party web servers and load balancers that you are using "in front" of Tomcat.

If you don't do any capacity planning before you buy and deploy your production servers, you won't know if the server hardware can handle your web site's traffic load. Or, worse still, you won't realize the error until you've already ordered, paid for, and deployed applications on the hardware—usually too late to change direction very much. You can usually add a larger hard drive or even order more server computers, but sometimes it's less expensive overall to buy and/or maintain fewer server computers in the first place. ...