RAID LEVEL 4: Independent Data Disks with Shared Parity Disk

 

Each entire block is written onto a data disk. Parity for same rank blocks is generated on Writes, recorded on the parity disk and checked on Reads.

RAID Level 4 requires a minimum of 3 drives to implement 

Characteristics & Advantages

  • Very high Read data transaction rate
  • Low ratio of ECC (Parity) disks to data disks means high efficiency
  • High aggregate Read transfer rate

Disadvantages

  • Quite complex controller design
  • Worst Write transaction rate and Write aggregate transfer rate
  • Difficult and inefficient data rebuild in the event of disk failure
  • Block Read transfer rate equal to that of a single disk

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