RAID 5 usable size Parity
data uses up the capacity of one drive in the array (this can be seen by comparing it with RAID 4
: RAID 5 distributes the parity
data across the disks, while RAID 4 centralizes it on one disk, but the amount of parity
data is the same). If the drives vary in capacity, the smallest of them sets the limit. Therefore, the usable capacity of a RAID 5 array is
, where N
is the total number of drives in the array and Smin
is the capacity of the smallest drive in the array.