parity
A method that provides complete data redundancy while requiring that only a fraction of the storage capacity of mirroring.
The data and parity blocks are divided between the physical disks so that if any single physical disk is removed (or fails),
the data on the physical disk can be reconstructed. Data is reconstructed by using the data on the remaining physical disks.
The parity data might exist on only one physical disk, or the parity data might be distributed between all of the physical
disks in the Redundant Array of Independent Disks (RAID) group.