Appendix D: About RAID
A Redundant Array of Independent Disk (RAID) provides better performance and reliability from combinations of drives than is possible with the same total storage space without RAID. This Appendix describes the various RAID levels supported by the
The following table shows the number of drives needed and supported for the controller according to RAID level.
Table 2 Drive number limits for a given RAID level
Array type | Minimum drive number | Maximum drive number |
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|
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RAID 0 | 2 | 6 |
|
|
|
RAID 1 | 2 | 2 |
|
|
|
RAID 5 | 3 | 6 |
|
|
|
RAID 10 | 4 | 6 |
|
|
|
RAID 50 | 6 | 6 |
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|
|
Types of volumes and arrays
Simple volume
A simple volume consists of a single drive.
Spanned volume
A spanned volume is created by joining, or concatenating, two or more drives. The drives do not have to be of equal capacity and are connected
RAID 0
A RAID 0 array is created by striping data across two or more drives. This striping scheme creates no redundancy to protect the data. However, because the drives share load equally, a RAID 0 array has the best read and write performance of any RAID type.
In the following figure, the Dn labels (D0, D1, and so on) denote consecutive blocks of data.
Figure 3 A RAID 0 array
Appendix D: About RAID 17