Asterisk activity generates events that will cause the creation of an entry in either the main system logs, or in Asterisk’s own logfiles. On a busy system (or a system that is experiencing a severe problem), these logfiles can grow very large, very quickly. If debugging is turned on, the processes involved in writing to these logfiles can begin to have an effect on system performance. By default, Asterisk will simply add to the files until the hard drive is full. Fortunately, Linux provides utilities to handle the rotation of logfiles (so that no single file becomes too large), and also the deletion of older logfiles (which will prevent the system from getting clogged with logfiles).

The logrotate utility is normally run once per day by the operating system. Unfortunately, since there is no script installed to instruct logrotate on how to handle Asterisk, its logfiles will grow unchecked until a rotate script is added to handle them. In order to make that happen, we need to set up parameters for Asterisk in a file in the /etc/logrotate.d directory. This file will need to rotate the current logfile, and then send Asterisk instructions to rotate its own logger (causing it to stop using the now old logfile, and generate a new file).

Create a new file /etc/logrotate.d/asterisk and place the following lines in it:

/var/log/asterisk/* /var/log/asterisk/cdr-csv {
missingok
sharedscripts
monthly
rotate 12
postrotate
    asterisk -rx "logger rotate" > /dev/null 2> /dev/null
endscript
}

This file tells the logrotate utility to rotate the Asterisk logs every month, save 12 months worth of logs, and then tell Asterisk that the logfiles have been rotated (which will cause Asterisk to create new logfiles and begin writing to them). We selected these values arbitrarily. Feel free to adjust them to suit your needs.