Configuring the hardware and installing an operating system
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.
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.
Dedicated spare
The dedicated spare drive activates any time a drive within the array fails.
Failure spare activation
Failure spare activation mode activates a spare drive when a member drive within an array fails using fault tolerance
methods to regenerate the data.
Assigning one or more online spare drives to an array enables you to postpone replacement of faulty drives.
To Next Page
Loading...
