RAID level 3 is organized in a similar fashion to RAID level 2. The difference is that RAID 3 requires only a single redundant disk.
RAID 3 allows parallel access, with data distributed in small strips.
Instead of an error correcting code, a simple parity bit is computed for the set of individual bits in the same position on all of the data disks.
In this event of drive failure, the parity drive is accessed and data is reconstructed from the remaining drives. Once the failed drive is replaced, the missing data can be restored on the new drive.