RAID 4

RAID 4 is a Level that uses a Dedicated Parity Drive, and is a commonly used implementation of RAID. Level 4 provides block-level striping (like RAID 0) with a dedicated parity disk. If a data disk fails, the parity data is used to create a replacement disk. A disadvantage to Level 4, is that the parity disk can create disk write bottlenecks, severely cutting performance.