Uses twice as many disks as RAID 0 (e.g., 8 smaller disks with
the second set of 4 duplicating the first set) so there are
always two copies of the data
# redundant disks = # of data disks so twice the cost of one big disk
writes have to be made to both sets of disks, so writes would be only 1/2
the performance of a RAID 0
What if one disk fails?
If a disk fails, the system just goes to the “mirror” for the data