Introduction › What to Expect from Performance Manager

What to Expect from Performance Manager

Performance Manager analyzes collected system data required for determining whether a specific resource is causing a performance problem. The data collected at your site may cause Performance Manager rules to fire. To fire means that when all the data has been processed, Performance Manager examines the count of a rule's occurrences, and if there are enough occurrences for a particular rule, that rule is said to fire. This causes an entry for that rule to be placed in the report file in the form of a conclusion. However, you can modify or disable Performance Manager rules or threshold values, which govern performance analysis.

When you request an Analysis Report, you may receive advice about performance problems for some of the following reasons:

• Inefficient setting of SYSGEN or UAF parameters
• Excessive demand
• Excessively long device queues
• Insufficient system resources
• Inefficient application design
• Insufficient hardware for the workload

Before you follow any Performance Manager recommendations, ask the following questions:

• Is the problem caused by a temporary condition?

  Performance Manager does provide summary analysis for extended time periods, such as weeks or months.

• How frequently does the problem occur?
• Is there a difference in the workload before and during the time the problem occurs? (Occasionally, the problem may be caused by the inherent characteristics of an application or workload.)

If Performance Manager recommends that you need additional hardware, keep track of this recommendation over a period of time. If system performance degrades, this recommendation occurs more frequently. You must decide whether the problem is serious enough to warrant additional hardware.

Never rely solely on Performance Manager recommendations. As you become familiar with the workload on your system, you develop your own ideas on how to recognize and alleviate performance problems. Use the Performance Manager as a tool to help you discover and resolve performance problems. Although you need the information Performance Manager provides for investigating any perceived performance problem, this information is not infallible. Occasionally, Performance Manager recommendations do not improve performance. Additional expertise, analysis, hardware, and tuning may be required to solve a specific performance problem.