Lately my /tmp folder was piling up with files (krb5cc*) without any signals that these files were regularly deleted. A bit of googling showed that these come from the Open Directory Server, but that's something I cannot control. So I went to investigate why the daily script would not delete them. I googled a bit again and found out where the parameter file for the daily, weekly and monthly cleanup-scripts is located: /etc/defaults/periodic.conf. There, I found these settings for /tmp :

# 110.clean-tmps
daily_clean_tmps_enable="YES"           # Delete stuff daily
daily_clean_tmps_dirs="/tmp"            # Delete under here
daily_clean_tmps_days="3"               # If not accessed for
daily_clean_tmps_ignore=".X*-lock .X11-unix .ICE-unix .font-unix .XIM-unix"
daily_clean_tmps_ignore="$daily_clean_tmps_ignore quota.user quota.group"
                                        # Don't delete these
daily_clean_tmps_verbose="YES"          # Mention files deleted

The one to look for is where it says "3". This indicates that the routine should clean up old files not accessed for 3 days. But it did not - and the files were not mentioned in the ignore-parameters. Even rm -rf krb5cc* returned immediately an error that its argument list was too long. Therefore I started reading what the exact values for this parameter should be.

Well, it turns out that the value needs a qualification, like d(ays) or m(months), etc.. I found that out by reading /etc/periodic/daily/110.clean-tmps and studying how find uses -atime, -ctime and -mtime and how to add or subtract values. Here are a few find-commands, copied from /etc/periodic/daily/110.clean-tmps, which I tried to make sure that what I just read was right:

$ cd /tmp
$ sudo find -dx . -fstype local -type f -atime +1h -mtime +1h -ctime +1h
$ sudo find -dx . -fstype local -type f -atime +1d -mtime +1d -ctime +1d
$ sudo find -dx . -fstype local -type f -atime +2d -mtime +2d -ctime +2d

Further reading suggested to use override-files, so I sudo'd into vi to create the file /etc/periodic.conf with the following contents:

daily_clean_tmps_days="2d"

Yes, 2 days. Three days is too long for a server, in my opinion. The file's attributes look like this:

marcvos @ ~ $ ls -l /etc/periodic.conf
-rw-r--r-- 1 root wheel 27 Oct 25 16:38 /etc/periodic.conf

Next, delete the file daily.out:

$ sudo rm /var/log/daily.out

Reboot the server. Check your /tmp folder and /var/log/daily.out the next days.

With me, I now finally saw all those files getting deleted.