How To Enable Process Accounting on Linux

Last updated: Fri Aug 8 09:25:58 HKT 1997


Preamble: This document is copylefted by Albert M.C. Tam (bertie@scn.org). Permission to use, copy, distribute this document for non-commerical purposes is hereby granted, provided that the author's / editor's name and this notice appear in all copies and/or supporting documents; that this document is not modified. This document is distributed in hope that it will be useful, but WITHOUT ANY WARRANTY, either expressed or implied. While every effort has been taken to ensure the accuracy of the information documented herein, the author / editor / maintainer assumes NO RESPONSIBILITY for errors, or for damages results for the use of the information documented herein.

This document describes how to enable system process accounting on a Linux host, and the usage of various process accounting commands. It is intended for users running kernel version greater than or equal to 1.3.73 (recently tested on RedHat 4.1 kernel 2.0.27). Kernels older than 1.3.73 may need a patch in order to use the process accounting feature.

Feel free to send any feedback or comments to bertie@scn.org if you find an error, or if any information is missing. I appreciate it.

What is Process Accounting?

Process accounting is the method of recording and summarizing commands executed on Linux. The modern Linux kernel is capable of keeping process accounting records for the commands being run, the user who executed the command, the CPU time, and much more.

Process accounting enables you to keep detailed accounting information for the system resources used, their allocation among users, and system monitoring.

Current Status of Process Accounting under Linux

Process accounting support has been integrated into the newer kernels (version >= 1.3.73). If you are running an older kernel, you may need some patch files. The patches are available from

Requirements for Process Accounting on Linux

Kernel

Linux Kernel version greater than or equal to version 1.3.73, I recommended 2.x. The kernel source is available from

Process accounting software

Depending on the Linux distribution you have, you may, or may not have the process accounting software package installed on your system. If you don't have it, try downloading the package from

Process Accounting Setup on Linux

1. Compile and install process accounting softwares

The process accounting software package is available from

2. Modify your system init script and turn on process accounting at boot time

Here's an example: 

	# Turn process accounting on. 
	if [ -x /sbin/accton ]
	then
        	/sbin/accton /var/log/pacct
        	echo "Process accounting turned on." 
	fi

3. Create accounting record file "pacct"

Your process accounting softwares will print out all commands executed to the file /var/log/pacct by default.

To create the accounting record file: 

	touch /var/log/pacct

This record file should be owned by root, has read-write permission for root, and read permission for anybody else: 

	chown root /var/log/pacct
	chmod 0644 /var/log/pacct

4. Reboot

Now reboot your system for changes you made to take effect.

Miscellaneous Process Accounting Commands

ac

ac prints out statistics about users' connection time in hours, based on the logins and logouts in the current /var/log/wtmp file. ac is also capable of printing out time totals for each day (-d option), and for each user (-p option).

accton

accton is used to turn on or turn off process accounting. The file is normally executed at system bootup or shutdown via system init scripts.

last

last goes through the /var/log/wtmp file and prints out information about connection times of users.

sa

sa summarizes accounting information from previously executed commands, software I/O operation times, CPU times, as recorded in the accounting record file /var/account/pacct.

lastcomm

lastcomm prints out the information about all previously executed commands, recorded in /var/account/pacct.