Look into the Accordance Systems raid devices. Find them here. They have internal and external drive devices.

We use the Internal version of the 2000, but there is an External Version as well. The system is 2 hard drives, but your PC will see them as a single drive. Remove one of the locakable drive trays, replace it with another drive, flip a swtich, go home, and in the morning you have 2 idential drives in your system. It is awesome, simple, relatively cheap, and great peace of mind of us here with our SQL database in one box and the important files on a 2nd box. I'm going to get one for my home network as well. Lots of storage, cheap!

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-'13 E93 M3 Cab, Interlagos Blue, Carbon Black leather, DCT, all options, and fun, endless fun!
-'13 X5 35i M-Sport, Carbon Black & Cinnamon, Dinan Stage 2!
-'15 Toyota Sienna Limited Premium AWD, Silver & Grey, Nav & BluRay, and less lame than the 2011 it replaced
-'07 Mini Cab S, Laser Blue, 6sp, endless fun that ended (sold)
-'04 X5 4.4i, loaded, loved, modded and sold