Fujitsu ETERNUS AF250 S2 - Figure 7 RAID6-FR Concept; Table 2 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 2 shows the comparison result of reliability, performance, capacity for each RAID level.
Table 2 RAID Level Comparison
RAID level Reliability Performance (*1) Capacity
RAID0
´
◎ ◎
RAID1
¡ ¡
△
RAID1+0
¡
◎ △
RAID5
¡ ¡ ¡
RAID5+0
¡ ¡ ¡
RAID6 ◎
¡ ¡
RAID6-FR ◎
¡ ¡
◎: Very good ¡: Good △: Reasonable ´: Poor
*1: Performance may differ according to the number of drives and the processing method from the host.
1. Function
RAID Functions
21
FUJITSU Storage ETERNUS AF250 S2, ETERNUS AF250 All-Flash Arrays
Design Guide (Basic)
Copyright 2019 FUJITSU LIMITED
P3AG-1822-09ENZ0