As I said on the other thread... For those contemplating an arranger (or any keyboard) that is dead in the water if the HD fails, first and foremost, backup is mandatory.

But I would also suggest you start to harass your manufacturer to consider a mirrored array of two HD's in the case. If you are not using SSHD's (and those are pretty expensive for ones big enough to handle live loops and sampler files), you are beating on your arranger (OK, playing it hard ) while the HD spins (and sometimes reads), probably not a recipe for long term reliability...

But an array (or at least, two separate drives that you could mirror manually) would be inexpensive (HD's cost pennies, these days ) and provide security and peace of mind for the professional player...