Fujitsu ETERNUS DX100 S3 - Figure 7 RAID6-FR Concept; Table 3 RAID Level Comparison

● RAID6-FR (Provides the High Speed Rebuild Function, and Striping with Double Distributed Parity)
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 7 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
■
Reliability, Performance, Capacity for Each RAID Level
Table 3 shows the comparison result of reliability, performance, capacity for each RAID level.
Table 3 RAID Level Comparison
RAID level Reliability Performance (*1) Capacity
RAID0
´
◎ ◎
RAID1
¡ ¡
△
RAID1+0
¡
◎ △
RAID5
¡ ¡ ¡
RAID5+0
¡ ¡ ¡
RAID6 ◎
¡ ¡
RAID6-FR ◎
¡ ¡
◎: Very good ¡: Good △: Reasonable ´: Poor
2. Basic Functions
RAID Functions
21
Fujitsu Storage ETERNUS DX100 S4/DX200 S4, ETERNUS DX100 S3/DX200 S3 Hybrid Storage Systems
Design Guide (Basic)
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