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Is there a maximum number of virtual users allowed for load testing? RRS feed

  • Question

  • We're investigating load testing tools and building an environment to do load testing in.

    Does Visual Studio put a limit on the number of virtual users that it will generate? 

    The other commercial products were looking at charge a licensing fee based on the number of virtual users.  I was wondering if VS 2005 had a similar limit.

    Since we don't have a seperate environment setup yet for load testing, I am reluctant to just try out a really large number of virtual users because I don't want to cause problems in our testing environment for functional testing.

    Wednesday, December 28, 2005 2:05 AM

Answers

  • There is no hard limit on the number of virtual users supported in a load test.  There is a practical limit on the number of virtual users per load test agent before you run out of machine resources on the agent machine,  but there is also no limit on the number of load test agents machines that can be used, so very high virtual user counts can be achieved by using multiple agents. 

    Licensing for the Visual Studio 2005 Team Test Load Agent is per-CPU rather than per user (see http://msdn.microsoft.com/vstudio/products/vsts/load/details/default.aspx).    

    As stated there, Microsoft has run load tests of a web test with 1,000 or more virtual users on one load test agent, but your mileage may vary significantly depending on many factors such as the processor speed of your agent machine, the amount of think time between requests in a web test, etc. 

    Note that you can also run the load test locally on a machine where you have VS (with the Team Test edition) installed without purchasing the Load Agent which should support almost as many virtual users as one load test agent.   If this doesn't generate enough load, it would at least give you a rough idea of the number of users that could be supported per load test agent.

     

     

    Thursday, December 29, 2005 7:51 PM
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