Understanding RAID Levels and Conceptswww.3ware.com 18Using Drive Capacity EfficientlyTo make the most efficient use of drive capacity, it is advisable to use drivesof the same capacity in a unit. This is because the capacity of each drive islimited to the capacity of the smallest drive in the unit.The total unit capacity is defined as follows:3 RAID 0RAID 1 with hot spareRAID 54 RAID 5 with hot spareRAID 10Combination of RAID 0, RAID 1, single disk5 RAID 6RAID 5 with hot spareRAID 10 with hot spareCombination of RAID 0, RAID 1, hot spare, single disk6 or more RAID 6RAID 6 with hot spareRAID 50Combination of RAID 0, 1, 5, 6,10, hot spare, single diskTable 3: Possible Configurations Based on Number of Drives# Drives Possible RAID ConfigurationsTable 4: Drive CapacityRAID Level CapacitySingle Disk Capacity of the driveRAID 0 (number of drives) X (capacity of the smallest drive)RAID 1 Capacity of the smallest driveRAID 5 (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)RAID 6 (number of drives - 2) x (capacity of the smallest drive)RAID 10 (number of drives / 2) X (capacity of smallest drive)RAID 50 (number of drives - number of groups of drives) X (capacity of thesmallest drive)
