RAID LEVEL 5: Stripping with Distributed Parity Blocks

Server
Disk 0
Disk 1
Disk 2
Disk 3
A
B
C
A0
A1
A2
Ap
B0
B1
Bp
B2
C0
Cp
C1
C2
Parity Generator(p)

Click on the diagram to see Raid 5 in action

RAID 5 consists of block-level striping with the parity information being distributed among the drives. It requires that all drives but one be present to operate.
RAID 5 requires at least 3 drives to implement.

Characteristics & Advantages

  • Highest Read data transfer rate
  • Somewhat slower Write data transfer rate
  • Upon failure of a single drive, subsequent reads can be calculated from the distributed parity; such that no data is lost.
  • Excellent security and decent performance

Disadvantages

  • Controller design is most complex
  • Drive failures has an effect on throughput, which is still acceptable
  • Rebuilding in the event of disk failure is difficult

Recommended Applications

  • File Servers
  • Database Servers
  • Application Servers
  • Practically any servers with limited data drives