Determining what size history files to allocate

The size of a history file to be allocated depends on several factors, such as the installation environment and the types of jobs for which faults are being recorded. However, the following can be used as an initial approximation of the space requirement expressed in kilobytes:
kilobytes = 500 * number-of-entries
The maximum number of concurrent entries that you want to hold in the history file.

A more accurate determination of the average fault entry size can be made by dividing the actual history file space utilization by the total number of members after having recorded a representative number of faults.

A suggested size of the initial history file is 100 cylinders. Allocate the history file with secondary space to avoid potential out-of-space conditions.