Performance Testing Microsoft® .NET Web Applications

Chapter 9. Estimating IIS Tier Capacity with Transaction Cost Analysis

Jonathan Swift said, “Necessity is the mother of invention;” but when you’re performing capacity planning, Mark Twain’s words are more applicable: “Necessity is the mother of taking chances.” Why? Because capacity planning is the art of reducing the probability that a Web application’s performance will degrade as a result of increasing or changing traffic patterns, while simultaneously avoiding unnecessary hardware purchases. Microsoft’s Transaction Cost Analysis (TCA) is a science-based methodology to help you estimate Web application hardware needs. But you can never predict with 100-percent certainty what a user population actually ends up doing with your Web application. ...