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Difference between RAID 3 and RAID 4

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1. 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. Advantages –

  1. Data can be transferred in bulk
  2. Data can be accessed in parallel.

Disadvantages –

  1. It require an additional drive for parity.
  2. In case of small size files it performs slowly.

 
2. RAID 4: RAID 4 consist of Block-level Striping. In this level entire set or block of data written onto the data disk and then the parity is generated and stored on a different set of disk. This level overcome at most one disk failure. If more than one disk failure occur then there is no way to recover the data. Both RAID 3 and RAID 4 require at least three disk to implement RAID. Advantages –

  1. It facilitates simultaneous I/O request because of Block striping.
  2. Storage overhead is low.

Disadvantages –

  1. Parity disk may lead to bottleneck.
  2. Slow random writes because of separate block parity.

Difference between RAID 3 and RAID 4 :

SR.No. RAID 3 RAID 4
1. RAID 3 stands for Redundant Array of Independent Disk level 3. RAID 4 stands for Redundant Array of Independent Disk level 4.
2. In RAID 3 technology, Byte-level Striping is used. In RAID 4 technology, Block-level Striping is used.
3. In this level, parity bits are generated for each disk section and stored on a different disk. In this level, parity bits are generated for the entire block of data and stored on a different disk
4. Random read will have worst performance. Good Random reads, as the data blocks are striped.
5. Performance is good in case of large sized files. Performance is low because only one block is accessed at a time

RAID (Redundant Array of Independent Disks) 3 and RAID 4 are both parity-based RAID configurations that use dedicated parity disks to provide data redundancy and protection against disk failure. However, the main difference between RAID 3 and RAID 4 is in the way they distribute data and parity across the disks.

  1. In RAID 3, data is striped across multiple disks, with one dedicated parity disk that stores the parity information for all the data disks. This means that the data can be accessed in parallel from multiple disks, which can result in faster read and write performance. However, because all the parity information is stored on a single disk, the parity disk can become a bottleneck for write performance.
  2. In RAID 4, data is also striped across multiple disks, but each disk has its own dedicated parity disk that stores the parity information for that particular disk. This means that each disk can operate independently, and there is no bottleneck for write performance caused by a single dedicated parity disk. However, because each disk has its own parity disk, the parity information cannot be accessed in parallel, which can result in slower read performance compared to RAID 3.

Overall, RAID 3 may be a better choice for applications that require high read and write performance, while RAID 4 may be a better choice for applications that require more balanced performance and protection against disk failure.


Last Updated : 03 May, 2023
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