Did you know the new Apple Mac Mini has enough space inside to install an extra second hard drive! The Apple Mac mini is a small power packed complete computer, simply add a monitor, wireless keyboard and mouse and you have a advanced desktop to work with. And if you could just add another hard drive inside the already compact Mac mini – nothing could be better.
Apple Mac Mini already comes powered with a 500GB (5400-rpm) hard drive, which is configurable to 750GB (7200-rpm) hard drive (2.5GHz model also configurable to 256GB solid-state drive or 256GB solid-state drive and 750GB (7200-rpm) hard drive, only at the Apple Online Store). The iFixit team performed a tear down of the Mac Mini and found enough space to install a second hard drive.
Extra Hard Drive in Mac Mini
Subsequently the ifixit guys launched a Mac Mini Dual Hard Drive Kit for users who want to add a second hard drive to Mac Mini. There is also a stepwise tutorial on how to install the extra hard drives to your Mac mini. Find more help on adding 2nd Hard Drive to Non-Server Minis.
Note: Remember this is not endorsed by Apple and may void your product warranty. So try it at your own risk if you know your way around exploring Mac mini.