Performance Monitoring

This section applies to all file pool servers as explained in Limit Monitoring. But, file pool repository server monitoring is more important than CRR or FIFO server monitoring.

Monitoring the performance of your system is optional. Your decision on whether to monitor performance should be based on the importance of response time at your installation. When response time is critical, it is advisable to do some monitoring to identify performance trends. This lets you take appropriate actions before performance becomes a problem. Further, to effectively solve performance problems it is often helpful to have performance data that was gathered prior to the time of poor performance. This data is used for comparisons. If you wait until a performance problem occurs, it will not be possible to create the comparison data.

Short-term actions involve tuning the system to optimize performance, while long-term actions include anticipating and planning for hardware needed to support increased capacity.

In addition to response time, the size of your processor and the number of users it supports also are factors in deciding the worth of monitoring performance. Performance adjustments are often relatively fine. Their effects tend to be amplified on larger systems. On smaller systems, however, the effect of many performance enhancements are not as greatly amplified and in some cases may be unnoticeable. Thus, it is often not worthwhile to monitor performance on smaller systems.

For example, suppose your department provides computer services to other departments in the same company. Suppose, also, that as part of your agreement, you must provide a certain maximum average response time. In this case it is well worth your time to continually monitor performance. You would try to identify performance trends so appropriate actions can be taken before performance violates your service agreement.

If, on the other hand, your processor is used for departmental operations, response time may not be as critical. On smaller processors that serve fewer users, performance monitoring will likely have marginal benefit. In this case, you might not do any performance monitoring. Instead, you would wait until performance became unacceptable and then take corrective action, as described in z/VM: Performance.

If you are interested in monitoring a server for performance, see z/VM: Performance. Also see Reorganizing the File Pool Repository Catalogs for more information that can affect performance.