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To test a Web farm, it is necessary to use Internet Protocol (IP) switching techniques to correctly simulate production because of server affinity for IP addresses. Application servers and Web servers are frequently multi-homed (that is, having more than one network interface card), with one facing the clients/Web server and another facing the Web server/database back end. This is done for security reasons and also to avoid network utilization on one network interface card for both types of traffic. Characteristics such as this can have a significant impact on performance test design, execution, and analysis. The performance tester will not be as effective if he or she is not accepted by the development team as a technical resource. By determining the system architecture, the performance tester can establish him or herself as a technical resource with the developers and architects.
Summary Although system evaluation is an ongoing process throughout the performance-testing effort, it provides the most value when conducted early in the performance-testing project. During the system evaluation process, collect information about the project as a whole, the functions of the system and/or business processes, the expected user activities, the system architecture, and any other details that are helpful in guiding performance testing in order to achieve the project’s specific needs. This information helps in defining the performance goals and requirements, characterizing the workload, creating performance test strategies and plans, and assessing project and system risks.