Correcting a moodle backup error in a large course

I have seen this before.  My colleague sent me a message this am that a largish course that she is trying to backup on our moodle 2.2 instance is failing.  The message from the moodle error logs says

"[Thu Apr 18 08:43:22 2013] [error] [client 10.3.12.30] PHP Warning:  Unknown: Input variables exceeded 1000. To increase the limit change max_input_vars in php.ini. in Unknown on line 0, referer: http://studentmoodle.accelerateu.org/student/backup/backup.php"

We found this moodle forum that suggested a tweak of the php.ini file for the server.

After scanning the php.ini file on the server, I did NOT see this variable, max_input_vars, so how could I adjust its setting?

I also found later in the discussion that I could manually add this variable to the file.  This makes me a little nervous, but worse case scenario, it crashes the web server and I remove it.

So, I scrolled to the bottom of the php.ini file, and added max_input_vars = 5000.

Then restarted Apache, for force a re-read of the php.ini file.

My colleague tried the backup again with success!