How To Enable Process Accounting on Linux

Last updated: Mon Jul 29 23:04:02 PDT 1996

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 (tested on
kernel 2.0.7). Kernels older than 1.3.73 will 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!

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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 new kernels (version
>= 1.3.73). If you are running an older kernel, you'll need to get some
patch files. The patches are available from

     ftp://iguana.hut.fi/pub/linux/Kernel/process_accounting

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

     ftp://tsx-11.mit.edu/pub/linux/sources/system/

Process accounting software

Depending on the Linux distribution you have, you may, or may not have the
accounting softwares installed on your system. The quota software source is
available from

     ftp://alpha.gnu.ai.mit.edu/gnu/acct-6.2.tar.gz

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Process Accounting Setup on Linux

1. Compile and install process accounting softwares

You may, or may not have the process accounting softwares, depending on the
Linux distribution you have. The process accounting software source is
available from

ftp://alpha.gnu.ai.mit.edu/gnu/acct-6.2.tar.gz

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

Here's an example:

        # Turn process accounting on.
        if [ -x /sbin/accton ]
        then
                /sbin/accton /var/account/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/account/pacct by default. To create the accounting directory:

        mkdir /var/account

To create the accounting record file:

        touch /var/account/pacct

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

        chown root /var/account/pacct
        chmod 0644 /var/account/pacct

4. Reboot

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

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Miscellaneous Process Accounting Commands

ac

ac prints out statistics about users' connect 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.