Estimating Your Performance Database Size Overview

Because performance monitoring can store a significant amount of data in your performance database, you may want to estimate the amount of data to be stored in your performance database so that you have, or are able to provide, the appropriate amount of space.

Performance database sizing estimates are based on the sum of space requirements for events and performance measurement unit (PMU) performance data. Event data resides in the PSPMEVENTHIST table. PMU data resides in the PSPMTRANSHIST and PSPMTRANSCURR tables.

This section presents formulas that you can use to estimate the potential size of your performance database.

These formulas incorporate the following assumptions and considerations:

• Performance Monitor is set to Standard agent filter mode.

• Estimates do not include space required for Verbose or Debug agent filter mode.

• Index overhead is included in the estimate.

• Performance history data is purged after a number of days (see parameter D in the following section).

• The archive mode of a monitored system is set to Delete Data after N days and the performance data archive program is scheduled to run daily.

• The reaper program is scheduled to run at least once a day.

• No performance data is stored in the archive tables (PSPMTRANSARCH and PSPMEVENTARCH).

• The calculation formulas use only the parameters that are presented in this section to calculate the estimates. In all cases, the numbers are conservative. For example, the exact formula may use (App – 1) but we choose to round up and use App instead.