Always remember hard drives will fail! If you keep this in mind, always have two copies on separate drives, then back up to LTO3. An LTO drive is so much cheaper than a re-shoot!
Also, try and make separate, redundant copies, bypassing any form of raid 1 setups. ifa raid controller fails, it may cost as much as a LTO drive to rebuild drive metadata.
I have learned from all conceivable worst-case scenarios. Beware.
Colin