Fujitsu Eternus2000 Manual page 30

1.2 Configuration
• RAID1+0 (striping of pairs of disks for mirroring)
RAID1+0 combines the performance of RAID0 (striping) with the reliability of RAID1 (mirroring).
Figure 1.3
• RAID5 (striping with distributed parity)
Data is allocated in units of blocks across multiple disks to duplicate data.
Figure 1.4
6
B
A
HDD1
A'
Mirroring
HDD0
HDD4
RAID1+0 Concept
Data writing request
A
A B
A B
E F
I J
M P
M, N, O, P
HDD0 HDD1
RAID5 Concept
Copyright 2009 FUJITSU LIMITED
Data writing request
A B C D
C
Mirroring
HDD2
B'
Mirroring
HDD5
B C D
C D Create Parity Data
C D
G P
E, F, G, H
P K
I, J, K, L
N O
HDD2 HDD3
Paruty for data A to D Parity A, B, C, D
Paruty for data E to H Parity E, F, G, H
Paruty for data I to L: Parity I, J, K, L
Paruty for data M to P Parity M, N, O, P
ETERNUS2000 disk storage system User Guide
D
Mirroring
HDD3
C'
HDD7
HDD6
Striping (RAID0)
Mirroring (RAID1)
P
A, B, C, D
H
L
P
HDD4
D'
P3AM-2512-03EN