unisys was here for 3 weeks setting it up - the right way. it's all mirrored and striped from one array to the other, and that's protected against any accidental deleting. the only thing that has any kind of access to the storage array on it is devices in the cabinet of the mainframe itself. it's a sweet setup.
since i work in banking, i should probably explain this a little better since not a lot of people work in my field...
all the terminals that process transactions feed a string of data to the TP (transaction processor) which are several processes that run on the mainframe, and the perform the transactions and change the data in the database fields required. it's pretty slick actually.