2
RAID Benefits and Tradeoffs
2-15
RAID Types and Tradeoffs
A RAID 1 mirrored pair or RAID 1/0 Group provides very high data
availability. They are more expensive than RAID 5 or RAID 3 Groups,
since only 50 percent of the total disk capacity is available for user
data, as shown on page 2-13.
A RAID 5 or RAID 3 Group provides high data availability, but
requires more disks than a mirrored pair. In a RAID 5 or RAID 3
Group of five disks, 80 percent of the disk space is available for user
data. So RAID 5 and RAID 3 Groups use disk space much more
efficiently than a mirrored pair. A RAID 5 or RAID 3 Group is usually
more suitable than a RAID 1 mirrored pair for applications where
high data availability, good performance, and efficient disk space
usage are all of relatively equal importance.
For a LUN in any RAID Group, to provide for disaster recovery, you
can establish a remote mirror at a distant site.
