How can I test an overload on a Mac OS X computer without potentially destroying the original data?

You can clone a faculty or staff person's startup disk to a secondary drive, like a FireWire disk. You can use Apple's Disk Utility or a third party tool like Carbon Copy Cloner. Then, move that cloned drive to another computer -- or even boot up the same computer from that secondary drive. It depends on your tolerance for risk, but it's a wise idea to not have the backup and original on the same computer before you potentially make wholesale filesystem changes.

Set up your Radmind config file so that the computer using that cloned backup drive has your test command file. Then, run an update and examine the results. Even better, have the person who uses the original examine the results. If you've lost data that you didn't expect to lose, you'll probably want to go back to the drawing board before deploying that command file and its transcripts to a real client.

Don't underestimate the value of secondary disks -- including FireWire drives -- as a Radmind administrator.