RAID
RAID -> Redundant Array of Independent Disks -> It is a method in which multiple hard disks are placed in parallel and are controlled as if they were one disk unit -> It has 6 Levels RAID0 to RAID6 RAID Levels -> RAID0 : Writes block of fixed size in multiple disks. -> RAID1 : Records same data on two disk for safety. -> RAID2 : Correct error -> RAID3 and RAID4 : Detect error -> RAID5 : each data block is assigned a parity value. Upon failure of a single drive, subsequent reads can be calculated from the distributed parity such that no data is lost. -> RAID6 : extends RAID 5 by adding another parity block. the data is recoverable even when two disks fail.