If you want to capture data relating to user names and process names, the UNIX Process Accounting function must be running while data capture is taking place. You do not need Process Accounting to be turned on if you only want to capture overview information about a system. It is needed if you want to build accurate Planner models and want to associate the load from users or commands with specific workloads.
If it is to be used, make a note of the location of the Process Accounting output file, pacct. This can vary from one UNIX implementation to another, and System Administrators can locate it anywhere they choose. Acquire must know where to find it. The usual locations of the pacct file are:
For UNIX variants: either /var/adm or /usr/adm
For Linux: /var/account
Refer to the section UNIX and Linux Process Accounting, for further information on Process Accounting