RAID 4 (redundant array of independent disks)
RAID 4 is a RAID configuration that uses a dedicated parity disk and block-level striping across multiple disks.
Because data is striped in RAID 4, the records can be read from any disk. However, since all the writes must go to the dedicated parity disk, this causes a performance bottleneck for all write operations.
RAID 4 is not commonly used.
