2.
Basic Functions
RAID Functions
●
RAID6 (Striping with Double Distributed Parity)
Allocating two different parities on different drives (double parity) makes it possible to recover from up to two
drive failures.
Figure 6 RAID6 Concept
A
A
E
I
M
P1
Drive#0
FUJITSU Storage ETERNUS DX500 S4/DX600 S4, ETERNUS DX500 S3/DX600 S3 Hybrid Storage Systems Design Guide (Basic)
Data writing request
A
B
C
D
B
C
B
C
F
G
P1
P2
J
P1
I, J, K, L
P2
M, N, O, P
M, N, O, P
Drive#1
Drive#2
Parity for data A to D: P1
Parity for data E to H: P1
Parity for data I to L: P1
Parity for data M to P: P1
Copyright 2019 FUJITSU LIMITED
D
Create parity data
P1
P2
A, B, C, D
D
P2
E, F, G, H
E, F, G, H
I, J, K, L
K
N
O
Drive#3
Drive#4
and P2
A, B, C, D
and P2
E, F, G, H
and P2
I, J, K, L
I, J, K, L
and P2
M, N, O, P
20
A, B, C, D
H
L
P
Drive#5
A, B, C, D
E, F, G, H
M, N, O, P
P3AM-7722-25ENZ0