How do I limit launchd log size on OS X?

Solution 1:

I couldn't find a way to do this within the .plist file, however using newsyslog (rotate log files) instead seems to be the way forward.

Steps:

• Edit /etc/newsyslog.conf
• Add the following syntax:

<log filename>   [owner:group]  mode count size when flags [/pid_file] [sig_num]

• Verify that the configuration file is correct with sudo newsyslog -nvv

So for example from the question, I'll add the following to /etc/newsyslog.conf:

/path/to/logfile.log               644  2     1000 *     J
/path/to/another_logfile.log       644  2     1000 *     J

• mode: 644 (root can change it, everyone else can read it)
• count: 2 (maximum number of archive files which may exist)
• size: 1000 (max log file size of 1000 kilobytes)
• when: * (log rotation solely depends on the size)
• flags: J (newsyslog should attempt to save disk space by compressing the rotated log file using bzip)

See the newsyslog manual for more information.