Well, it took a little persistence, but I was able to get RAID 1 (Mirroring) of the two 500GB internal disks in my new Mac Mini Server, WITHOUT reinstalling the O.S., or even touching the DVD for that matter! Since I had been anxious to setup my new server as soon as I got it, I had already configured my web server settings, PHP code, etc., and only then paid any attention to the RAID issue. Since it ships in JBOD (Just a Bunch Of Disks) form, it wouldn't allow me to just unmount and add the second disk as a mirror. I didn't have the portable Apple SuperDrive nor necessarily want to reinstall. But I did have a spare USB hard drive, Mac Mini form factor even! So, I used SuperDuper (great app, used it, and paid for the registered version! to clone the Server HD to the external USB. My external drive is 300GB, just to illustrate that it doesn't have to be identical to the internal 500GB drive(s), and since only 7GB is taken in a basic config, even with my web pages, you might even be able to do this with an 8 or 16GB USB drive! Not a bad idea, for a spare backup. In fact, when I get my web server completely configured, I'll put a spare image on a 16GB USB as an offsite backup. So, using SuperDuper, I cloned the disk AND MADE THE EXTERNAL DRIVE BOOTABLE ('Set as Startup Disk'). Booted from the external drive, then used Disk Utility (RAID Utility is in the Operating System / Applications folder but does NOT work) to turn the internal disks (Server HD and Macintosh HD) into a new RAID Mirrored Pair. Note that this wipes the original drives. Then, I used SuperDuper again, to clone my EXTERNAL USB DRIVE back onto the new RAID Mirrored Pair. I made the RAID pair bootable ('Set as startup disk') and crossed my fingers. HOWEVER IT DIDN'T WORK. I tried booting from the internal RAID Mirror and got the "Prohibition" or universal 'NO' symbol... ironically, the same one in my logo, for No Tie Software!!! A cruel joke! I did some Googling (on my functional Macbook Pro) and learned that by holding the Option key down, at boot time, I could choose to boot from my working External drive. Also learned that the ALT key on a PC keyboard (which I was using) works as the Option key for a Mac! So, back into SuperDuper, running off the external USB drive, and this time I used the SmartUpdate feature (which requires a paid/registered version of SuperDuper). That did the trick. Upon reboot, I am running off the internal, RAID Mirrored drives (I'm typing this from the Mac Mini Server), plus I have a bonus backup on my external USB drive! Your mileage may vary, and I certainly don't want to be responsible for anyone wrecking a working production system. I would recommend doing this BEFORE you have any important data on the drives. Let me know how it goes!