Today I needed to tweak the startup order of various processes on our RHEL3 server at work. I needed to make sure that the lmtp server (which handles local delivery of messages to our mail database) started before Postfix. If this order was violated, all sorts of bad stuff could happen (like lost mail).
What I found was a bizarre solution, but it works (I’m guessing because I haven’t had the opportunity to restart the server yet).
In the /etc/rc?.d/ directories you place symbolic links to the startup scripts. By naming these links carefully you can specify the order of startup for that particular runlevel. It seems that there is a convention of naming these files S00script_name, so I would recommend sticking to it.
Unfortunately Webmin doesn’t allow for re-ordering startup actions and seeing as I find the startup actions in Linux some of the most complicated things to set up, it is a shame this feature is missing. (You can view the order though)
If I have it entirely wrong, let me know.