Whether you get it or not, RAID 5 works. Suffice it to say I have a RAID 5 array as a Time Machine drive. It is very fast and very reliable. The "trick" is the data is distributed across the various disks with a reliability algorithm that enables the contents of any one of the disks to be recreated from the contents of the remaining disks. Speed is gained because reading and writing is buffered across multiple disks. I actually tested my array by removing and replacing a disk while the array was running. During the recovery it was slower and it did take a while to recover, but recover it did. It won't replace your off site storage but it is far less complicated and labor intensive than your system, my backups occur every hour, and I can recover a given file or even the entire system from any single month, week, day, hour since the backup set was created.And yes I have had to go back a few hours in history to recover the entire system and it worked perfectly.
