8.7. Tools for Load Testing
There are many performance testing suites available on the market today that can cost as much as a brand-new Lamborghini. This section will show how a few of the less-expensive tools work. This section is intended to apply the practices discussed throughout this chapter to readily available testing tools.
The Web Capacity Analysis Tool (WCAT) is a HTTP load generation tool designed to measure the performance of a web application. WCAT ships in various versions of the IIS resource kit, or can be downloaded separately http://www.iis.net/downloads/default.aspx?tabid=34&g=6&i=1466. WCAT is a free tool, which is why so many developers/testers use it for performance testing. WCAT is a command line tool, which pushes some developers/testers away. The architecture of WCAT is common to many other performance testing tools with a controller that will control the performance test, and clients which connect to the controller to distribute load.
WCAT has been around for more than 10 years, and contains many configuration options to set the finest detail needed for an efficient performance test. When starting the WCAT controller, paths to configuration files are passed in. These configuration files contain the actual requests the test will be executing and other various performance test information such as warm up time and number of virtual clients to simulate. There are two common ways of specifying the configuration files, using text files or ubr files, ...