Accusys ExaRAID GUI - Manual (Page 266)

Appendix
A-10
A.9 RAID 50
RAID 50 arrays are formed by striping data across RAID 5 sub-arrays.
Striping helps increase capacity and performance without adding disks
to each RAID 5 array (which will decrease data availability and affect
performance when running in a degraded mode). Storage efficiency
and fault tolerance vary, depending on the number and size of the sub-
arrays compared to the array as a whole. As mentioned above, RAID 50 is
similar to RAID 30 in terms of characteristics but is more suitable for use
with smaller files.
RAID 50: Block striping with distributed parity combined with block striping
Characteristics
• Storage capacity = [(number of disks in each subarray) -1] x (number of
subarrays) x (capacity of the smallest disk)
• A minimum of six disks are required.
• More fault tolerant than RAID 5
• High data transfer rate
• RAID 0 striping ensures high I/O rates
Recommended use
• Applications requiring random positioning performance
• Large databases
Striping
A
E
P
IK
M
C
P
EG
K
O
P
AC
G
I
P
MO
B
F
P
JL
N
D
P
FH
L
Q
P
BD
H
J
P
NQ
RAID 5 RAID 5
AC
EG
IK
MO
BD
FH
JL
NQ
E
F
Logical Volume
A . . . Q
Figure A-8 RAID 50 disk array