Redundant Array of Inexpensive Disks

(abbr. RAID): Within a RAID drive, the data stream is split across several hard disks running in parallel and stored redundantly. The most commonly used methods are RAID 1 (mirror disks) and RAID 5. RAID 5 provides the same level of security as mirror disks, but the write speed is increased by parallel access to three or four hard disks. Intelligent partitioning of the disks also results in a higher capacity of the overall system compared to mirroring.

Source: logipedia / Fraunhofer IML