Fujitsu ETERNUS DX100 S5 - Figure 2 RAID6-FR Concept

● 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.
● RAID6-FR (Striping with Double Distributed Parity which Provides High-Speed Rebuild Capabilities)
Distributing multiple data groups and reserved space equivalent to hot spares to the configuration drives
makes it possible to recover from up to two drive failures. RAID6-FR requires less build time than RAID6.
Figure 2 RAID6-FR Concept
RAID6-FR ((3D+2P) × 2 + 1HS)
H
FHS
V
E
I
S
C
J
A
K
FHS
X W
F
FHS
N
T
G
Q
U
D
O
FHS
B
R
FHS
P
FHS
M
L
A B C D
Data writing request
A B C D
Create parity data Create parity data
P1 A, B, C
P1 P, Q, RP2 P, Q, R
P1 V, W, X
P1 M, N, O
P2 M, N, O
P1 D, E, F
P2 J, K, L
P2 D, E, F
P1 J, K, L
P1 S, T, U
P2 G, H, I P1 G, H, I
P2 S, T, U
P2 A, B, C
P2 V, W, X
Drive#0 Drive#1 Drive#2 Drive#3 Drive#4 Drive#5 Drive#6 Drive#7 Drive#8 Drive#9 Drive#10
Parity for data A, B, C: P1 A, B, C and P2 A, B, C
Parity for data D, E, F: P1 D, E, F and P2 D, E, F
Parity for data G, H, I: P1 G, H, I and P2 G, H, I
Parity for data J, K, L: P1 J, K, L and P2 J, K, L
Parity for data M, N, O: P1 M, N, O and P2 M, N, O
Parity for data P, Q, R: P1 P, Q, R and P2 P, Q, R
Parity for data S, T, U: P1 S, T, U and P2 S, T, U
Parity for data V, W, X: P1 V, W, X and P2 V, W, X
:
Fast recovery Hot Spare: FHS
2. Basic Functions
RAID Functions
34 Design Guide