RAID (often referred as the redundant arrays of independent disk or redundant arrays of inexpensive disk) refers to a technology using which we can get enlarged storage dependability through redundancy. It is achieved by combining multiple low cost and less reliable disk drives into an array of logical unit that are interdependent.

The levels of RAID are the basic set by which RIAD is configured. This employs parity, mirroring or stripping. There are currently 7 major RAID levels, RAID 0, RAID 1, RAID 2, RAID 3, RAID 4, RAID 5 and RAID 6.

RAID 0

This is achieved by block-level stripping without mirroring or parity. This give improved performance and an additional storage but no fault tolerance or redundancy. In this level of RAID a single disk failure can do a lot of damage as compared to disk drives without RAID. The more disks involved in RAID 0 the more is the risk involved. However, the bandwidth is increased with the number of disks.

RAID 1

In this level the disks are mirrored without stripping or parity. The data gets written in an identical form in multiple disks. This array offers fault tolerance and keeps on working even if a single mirrored set of the disks is functioning.

RAID 2

This level of RAID involves a synchronized disk spindle rotation. The data is stripped in such a way that every sequential bit stays at different disk. In RAID 2 large amount of data transfer is possible.

RAID 3

It involves the same technology as the RAID 2 but the data is stripped here in a way that every sequential byte stays on different disk. The data transfer rate is very high in RAID 3.

RAID 4

This confines all the parity of data into single disk. This creates performance bottleneck. This setup can be done with the distribution of files into multiple disks.

RAID 5

In this setup, the block-level stripping is done with distributed parity.

RAID 6

In this setup, the block-level stripping is done with double distributed parity. Double parity give an advantage of rebuilding of array without risking the data if a single drive fails to function before the completion of the rebuild.

The raid recovery procedure of all these levels to recover files can be done using raid data recovery software available in the market.