Capacity Planning Best Practices

There exist a number of best practices that should be followed when capacity planning for a WebLogic deployment:

Be conservative with your capacity estimates. The steps detailed in this chapter are able to provide a high-level estimate of the configuration required to meet your deployment goals. Capacity planning for WebLogic is not an exact science. For this reason, it is a best practice to err on the side of caution in terms of estimates. Many successful deployments take server hardware capacity-planning estimates and increase them by 50 percent in order to be absolutely sure that they will have adequate capacity. For deployments where absolute reliability is preferable over cost savings, this is a common practice.

Load test your application. There are a great number of things that can go wrong in terms of an application's capacity that can never be identified until the application is deployed in practice. For this reason, you should plan to load test your application either in a prototype form or using the hardware that you plan to deploy upon.

Optimize your application. The application built on top of WebLogic is often the most limiting factor to capacity. For this reason, you should plan to optimize your application during the testing process. There are a number of tools that provide you with insight as to hot spots and inefficiencies in your application based on WebLogic:

• jProbe from the KL Group (http://www.klgroup.com/) and OptimizeIT from Intuitive Systems, Inc. (http://www.optimizeit.com) can be used at development time to find bottlenecks in the code.

• Introscope from Wily Technology (http://www.wilytech.com) is a Java product that allows for runtime performance monitoring of any Java component in WebLogic. This tool is designed for monitoring production systems and not for tuning during development.

Plan for growth. One of the major benefits of WebLogic is that it is easily extensible. Growing a cluster is as simple as adding another server machine.

Most WebLogic deployments start small, but grow substantially over time as more clients and services come online. For this reason, it is a good practice to plan your WebLogic deployment for growth. You may want to choose a LAN infrastructure that is larger than your current deployment so that it is ready when you want to grow.

In terms of external connectivity to other resources such as the Internet or legacy systems, the bandwidth and hardware resources should be extensible. Many ISPs offer instant upgrades to Internet connections for higher bandwidth.