RAID Level 4

• Block level parity.

• Read requires the relevant disk.

• Write requires the relevant disk and the parity disk.

• Recovery from failure is simple (XOR).

• High I/O request.

• Can you see a performance problem?

block 0

block 4

block 8

block 12

block 1

block 5

block 9

block 13

block 2

block 6

block 10

block 14

block 3

block 7

block 11

block 15

P(0-3)

P(4-7)

P(8-11)

P(12-15)

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