Establish system benchmarks before you install a new version of the operating system or make a major system configuration change such as adding a new software application.
Accurate system benchmarks allow you to compare system performance before and after the upgrade. A valid comparison allows you to accurately assess any performance improvement as well as isolate any changes to the system that can prevent optimal performance.
Collection Services can collect sample data for a wide range of system resources. Collection Services stores sample performance data in a collection object (*MGTCOL) on your system. Minimally, benchmarks should include data from current and representative collection objects. This can require that Collection Services run long enough to collect representative data. Representative data should include all periods of activity (both peak and off-peak hours), all applications, and all normal activities performed on a system. Additionally, you might require more detailed benchmark information to identify how critical applications, transactions, and jobs are affected by the system configuration change.
Several tools are available for collecting detailed information about application performance. However, these tools can require specialized skills and could adversely affect system performance. For details about collecting different types of performance data, refer to Research a performance problem in the iSeries™ Information Center.