System information

Appendix
A-9
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
PIK
M
C
PEG
K
O
PAC
G
I
PMO
B
F
PJL
N
D
PFH
L
Q
PBD
H
J
PNQ
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