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RAID 60 RAID 60
RAID 60 is a nested RAID method in which the constituent drives are organized into several identical RAID 6 logical drive sets (parity
groups). The smallest possible RAID 60 configuration has eight drives organized into two parity groups of four drives each.
For any given number of hard drives, data loss is least likely to occur when the drives are arranged into the configuration that has the
largest possible number of parity groups. For example, five parity groups of four drives are more secure than four parity groups of five
drives. However, less data can be stored on the array with the larger number of parity groups.
The number of physical drives must be exactly divisible by the number of parity groups. Therefore, the number of parity groups that
you can specify is restricted by the number of physical drives. The maximum number of parity groups possible for a particular number
of physical drives is the total number of drives divided by the minimum number of drives necessary for that RAID level (three for RAID
50, 4 for RAID 60).
A minimum of 8 drives is required.
The maximum number of drives supported for RAID 60 is 256.
All data is lost if a third drive in a parity group fails before one of the other failed drives in the parity group has finished rebuilding. A
greater percentage of array capacity is used to store redundant or parity data than with non-nested RAID methods.
This method has the following benefits:
Higher performance than for RAID 6, especially during writes.
Better fault tolerance than RAID 0, 5, 50, or 6.
Up to 2n physical drives can fail (where n is the number of parity groups) without loss of data, as long as no more than two failed
drives are in the same parity group.
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