Sun Java Enterprise System Deployment Planning Guide


Business requirements typically express performance in nontechnical terms that specify response time. For example, a business requirement for web-based access might state the following:

Users expect a reasonable response time upon login, typically no greater than four seconds.

Starting with this business requirement, examine all use cases to determine how to express this requirement at a system level. In some cases, you might want to include user load conditions determined during usage analysis. Express the performance requirement for each use case in terms of response time under specified load conditions or response time plus throughput. You might also specify the allowable number of errors.

Here are two examples of how to specify system requirements for performance:

Performance requirements are closely related to availability requirements (how failover impacts performance) and latent capacity (how much capacity is available to handle unusual peak loads).