3Ware 9550SX-4LP User Manual page 20

Chapter 1. Introducing the 3ware® 9000 Series Controller
Table 3: Possible Configurations Based on # of Drives
# Drives
1
2
3
4
5
6 or more
Drive Capacity Considerations
The capacity of each drive is limited to the capacity of the smallest drive in
the array. The total array capacity is defined as follows:
Table 4: Drive Capacity
RAID Level
RAID 0
RAID 1
RAID 5
RAID 10
10
Possible RAID Configurations
Single drive or hot spare
RAID 0 or RAID 1
RAID 0
RAID 1 with hot spare
RAID 5
RAID 5 + hot spare
RAID 10
Combination of RAID 0, RAID 1, single disk
RAID 5 + hot spare
RAID 10 + hot spare
Combination of RAID 0, RAID 1, hot spare, for single disk
RAID 50
Depending on the number of drives, a RAID 50 may contain from
2 to 4 subunits. For example, with 12 drives, possible RAID 50
configurations include 2 subunits of 6, 3 subunits of 4, or 4
subunits of 3. With 10 drives, a RAID 50 will contain 2 subunits of
5 drives each. With 16 drives, a RAID 50 will contain 2 subunits
of 8 drives or 4 subunits of 4 drives.
Combination of RAID 0, 1, 5, 10, hot spare, and single disk
Capacity
(number of drives) X (capacity of the smallest drive)
capacity of the smallest drive
(number of drives - 1) X (capacity of the smallest drive)
Storage efficiency increases with the number of disks:
storage efficiency = (number of drives -1)/(number of drives)
(number of drives / 2) X (capacity of smallest drive)
3ware Serial ATA RAID Controller User Guide