HP SureStore E Disk Array FC60 Service Manual (A5635A)

Disk Array High Availability Features 55
Product Description
RAID Level Comparisons
To help you decide which RAID level to select for a volume group, the following tables
compare the characteristics for the supported RAID levels. Where appropriate, the relative
strengths and weakness of each RAID level are noted.
Table 1
RAID Level Comparison: Data Redundancy Characteristics
RAID Level Disk Striping Mirroring Parity
Handle multiple disk
failures?
RAID 0 Yes No No No. RAID 0 offers no data
redundancy or protection
against disk failure.
RAID 1 No Yes No No
RAID 0/1 Yes Yes No Yes, providing both disks in
a mirrored pair do not fail.
RAID 3 Yes No Yes No
RAID 5 Yes No Yes No
Table 2
RAID Level Comparison: Storage Efficiency Characteristics
RAID Level Storage Efficiency
RAID 0 100%. All disk space is use for data storage.
RAID 1 and 0/1 50%. All data is duplicated, requiring twice the disk storage for a
given amount of data capacity.
RAID 3 and 5 One disk’s worth of capacity from each volume group is required to
store parity data. As the number of disks in the volume group
increases, so does the storage efficiency.
3-disk volume group: 66%
4-disk volume group: 75%
5-disk volume group: 80%
6-disk volume group: 83%