This article provides a list of tools you can use to simulate load for your Web applications. By simulating load for your application, you can test concurrency issues as well as better understand how your application behaves under stress. Testing load and concurrency by refreshing a browser is not considered a valid test.

The following Web stress tools are available from Microsoft:

Web Capacity Analysis Tool • The IIS 6.0 Resource Kit Tools include WCAT 5.2. To download the IIS 6.0 Resource Kit Tools, visit the following Microsoft Web site: http://www.microsoft.com/downloads/details.aspx?FamilyID=56fc92ee-a71a-4c73-b628-ade629c89499&DisplayLang=en (http://www.microsoft.com/downloads/details.aspx?FamilyID=56fc92ee-a71a-4c73-b628-ade629c89499&DisplayLang=en) • The IIS 7.0 Web Capacity Analysis tool can be downloaded from the following Microsoft Web site: http://www.iis.net/downloads/default.aspx?tabid=35&g=6&CreatedBy=IISTeam (http://www.iis.net/downloads/default.aspx?tabid=35&g=6&CreatedBy=IISTeam)

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Web Application Stress Tool To download the Web Application Stress Tool, visit the following Microsoft Web site: http://www.microsoft.com/downloads/details.aspx?FamilyID=e2c0585a-062a-439e-a67d-75a89aa36495&DisplayLang=en (http://www.microsoft.com/downloads/details.aspx?FamilyID=e2c0585a-062a-439e-a67d-75a89aa36495&DisplayLang=en)

With these tools you can stress test your Web server to see how it reacts when several hundred users access your application at peak times. These tools can also be used to test the server-side components for performance, locks, and other scalability issues. A Web application that relies on databases can also be tested on parameters such as concurrency, transactions, number of users, locks, pooling, and so forth.