Validation phase - System Testing - Performance Testing - Capacity Planning and Bug Fixing

Most traditional applications are designed to respond to a single user at any time, most web applications are expected to support a wide range of concurrent users. As a result, performance testing has become a critical component in the process of deploying a web application. Performance testing has proven to be most useful in the capacity planning area.

- Capacity Planning
Capacity planning is about being prepared. Suppose if you want to know if your server configuration is sufficient to support two million visitors per day with average response time of less than five seconds etc. In capacity planning, you need to set the hardware and software requirements of your application so that you will have sufficient capacity to meet anticipated and unanticipated user load. One approach in capacity planning is to load-test your application in a testing server farm. By simulating different load levels on the farm using a web application performance testing tool such as WAS, you can collect and analyze the test results to better understand the performance characteristics of the application. Also, you may want to test the scalability of the application with different hardware configurations. You should load test your application with different numbers of clustered servers to confirm that the application scales well in cluster environment.

- Bug Fixing
There are some errors that may not occur until the applications is under high user load. Performance testing helps to detect and fix such problems before launching the application. It is therefore recommended that developers take an active role in performance testing their applications, especially at different major milestones of the development cycle.