assumed. Table 5.4 describes the RAID levels, including the number of drives required, and the capacity.
Table 5.4 | Capacity for RAID Levels | ||||
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| |
RAID |
|
| Drives |
| |
Level | Description | Required | Capacity | ||
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|
|
| |
0 | Striping | 1 | – 30 | (Number of disks) X capacity of | |
| without parity |
|
| smallest disk | |
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|
|
|
| |
1 | Mirroring | 2 |
| (Capacity of smallest disk) X (1) | |
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|
|
|
| |
5 | Striping with | 3 | – 30 | (Number of disks) X (capacity of | |
| floating parity |
|
| smallest disk) - (capacity of 1 disk) | |
| drive |
|
|
| |
|
|
|
| ||
10 | Mirroring and | 4 – 30 | (Number of disks) X (capacity of | ||
| Striping | (Must be a | smallest disk) / (2) | ||
|
|
| multiple of 2.) |
| |
|
|
|
|
| |
50 | RAID 5 and | 6 | – 30 (Must | (Number of disks) X (capacity of | |
| Striping | be a multiple | smallest disk) – (capacity of 1 disk X | ||
|
|
| of the # of | number of arrays) | |
|
|
| arrays.) |
| |
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|
|
|
5.3.1.2Maximizing Drive Availability
You can maximize the availability of data on the physical disk drive in the logical array by maximizing the level of fault tolerance. Table 5.5 describes the levels of fault tolerance for the RAID levels.
Table 5.5 | Fault Tolerance for RAID Levels |
| ||
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|
| |
RAID Level |
| Fault Tolerance Protection |
| |
|
|
|
| |
0 |
| No fault tolerance. |
| |
|
|
|
|
|
1 |
| 100% | protection through data mirroring. |
|
|
|
| ||
5 |
| 100% protection through striping and parity. The data is striped | ||
|
| and parity data is written across a number of physical disk |
| |
|
| drives. |
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|
|
|
|
|
|
10 |
| 100% | protection through data mirroring. |
|
|
|
|
| |
50 |
| 100% | protection through data striping and parity. All data is | |
|
| striped and parity data is written across all drives in two or | ||
|
| more arrays. |
| |
|
|
| ||
Creating Logical Drives | ||||
Copyright © 2002 by LSI Logic Corporation. All rights reserved.