1. RAID 2:
It consist of Bit-level Striping. RAID 2 records Error Correction Code (ECC) using hamming code parity. In this level each data bit in a word is recorded on a separate disk and ECC codes of the data words are stored on a different set of disk.
- In case of Error Correction it uses hamming code.
- It Uses one designated drive to store parity.
- It has complex structure and high cost due to extra drive.
- It require extra drive for error detection.
2. RAID 3:
RAID 3 consists of Byte-level Striping. It stripes the data onto multiple disk. The parity bit generated for each disk section and stored on a different dedicated disk. This level overcome the single disk failure.
- Data can be transferred in bulk.
- Data can be accessed in parallel.
- It require an additional drive for parity.
- In case of small size files it performs slowly.
Difference between RAID 2 and RAID 3 :
|SR.No.||RAID 2||RAID 3|
|1.||RAID 2 stands for Redundant Array of Independent Disk level 2.||RAID 3 stands for Redundant Array of Independent Disk level 3.|
|2.||In RAID 2 technology, Bit-level Striping is used.||In RAID 3 technology, Byte-level Striping is used.|
|3.||In this level, One group of disk are used to write the data and other group is used to write the ECC.||In this level, Multiple disks are used for storing data and one dedicated disk is used to store parity|
|4.||Hamming code is used for Error detection.||Hamming code is not used.|
|5.||It require extra drive for Error Code.||It require extra drive for Parity.|
|6.||If one of the disk fails, the remaining bits of the byte and the associated ECC bits can be used to reconstruct the data.||In case of drive failure the parity bits is accessed and data is reconstructed from the remaining drive.|