webmin/logrotate/help/intro.html

<header>Log File Rotation</header>

Log file rotation refers to the automatic truncation, compression and
deletion of log files so that they do not consume too much disk space.
Most Unix servers (such as Apache, Squid and Sendmail) generate log files,
and various system daemons also create logs through Syslog. This module
can be used to configure the <tt>logrotate</tt> program to manage all those
logs. <p>

Typically, a log file will be rotated once every day, week or month. The file
is usually moved to a new filename and compressed, and a new empty file 
created in its place. Several generations of these old log files can be
kept, so that you can search or generate reports from them even after
rotation. Once the number of old logs exceeds a configured limit, the oldest
will be deleted. <p>

Each log file being rotated is listed on the module's main page. Each log
has its own set of options to control how often it is rotated, how many
old copies are kept and so on. You can edit the options for a log by clicking
on its filename, or add a new log file using the link at the bottom or top
of the table. <p>

Many Linux distributions include <tt>logrotate</tt> as standard, and come with
configurations for rotating the logs of included servers like Apache and
Squid. So even if you have never used this module before, many log files
may already be listed on the main page. Often 

Near the bottom of the page is a button for editing the global configuration,
which applies to all log files unless overridden. Below it is a button for
setting the schedule on which <tt>logrotate</tt> is run by Cron, which is
necessary for it to actually rotate logs. On most
operating systems that include the program as standard, a Cron job will
have been already created as part of the installation process. <p>

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