Today i would like to present a basic idea regarding RAID.
It is a combination of multiple small and inexpensive disks in the form of an array to accomplish performance and redundancy goals which is not attained to gain by large disk drives.This type of drive appear like as a single storage unit or drive.
In the RAID method information is spread across different drives using some of existing techniques called,disk stripping (RAID LEVEL 0), disk mirroring (RAID LEVEL 1),disk stripping with parity(RAID LEVEL 5) to achieve redundancy, lower latency and/or increase bandwidth for reading and writing to disks and maximize the ability to recover from hardware crashes .
RAID existence of different levels:
RAID 0:Non Redundant and data striping.
RAID 1: Redundant Mirroring.
RAID 3:Redundant parity disks.
RAID 5: Redundant distributed parity
RAID 6:Redundant distributed parity(P+Q)