The importance of a performance history

If you have a history of the performance of your system, you can begin to track the cause of problems as soon as users report slow response or inadequate throughput.

If a history is not available, you must start tracking performance after a problem arises, and you might not be able to tell when and how the problem began. Trying to identify problems after the fact significantly delays resolution of a performance problem.

To build a performance history and profile of your system, take regular snapshots of resource-utilization information.

For example, if you chart the CPU utilization, paging-out rate, and the I/O transfer rates for the various disks on your system, you can begin to identify peak-use levels, peak-use intervals, and heavily loaded resources.

If you monitor fragment use, you can determine whether your fragmentation scheme is correctly configured. Monitor other resource use as appropriate for your database server configuration and the applications that run on it.

Choose tools from those described in the following sections, and create jobs that build up a history of disk, memory, I/O, and other database server resource use. To help you decide which tools to use to create a performance history, this chapter briefly describes the output of each tool.