unRAID Array

unRAID Array

The primary concept behind an unRAID array is it’s ability to manage an aggregate of disk devices (JBOD) that is protected by a dedicated parity device. A parity device provides a way for you to reconstruct data from a failed disk onto a new one.  While it seems mind boggling that one drive can possibly back up other drives that have way more storage capacity than the parity, it is able to reconstruct the missing data from a failed drive using binary logic called XOR (eXclusive OR).  Since hard drives store data in zeroes and ones, when a drive fails the parity compares the binary data on all the drives and can deduce the missing data to rebuild.