Configuration Strategies
The most important factors in RAID array configuration are: drive capacity, drive availability (fault tolerance), and drive performance. You cannot configure a logical drive that optimizes all three factors, but it is easy to choose a logical drive configuration that maximizes one factor at the expense of the other two factors, although needs are seldom that simple.
Maximize Capacity RAID 0 achieves maximum drive capacity, but does not provide data redundancy. Maximum drive capacity for each RAID level is shown below. OEM level firmware that can span up to 4 logical drives is assumed.
RAID |
| Description |
| Drives |
| Capacity |
Level |
|
|
| Required |
|
|
0 | Striping | 1 – 32 |
| without parity |
|
|
|
|
1 | Mirroring | 2 |
|
|
|
3 | Striping with | 3 – 8 |
| fixed parity |
|
| drive |
|
(Number of disks) X capacity of smallest disk
(Capacity of smallest disk) X (1)
(Number of disks) X (capacity of smallest disk) - (capacity of 1 disk)
5 | Striping with | 3 – 8 | (Number of disks) X (capacity of |
| floating parity |
| smallest disk) - (capacity of 1 disk) |
| drive |
|
|
10 | Mirroring and | 4 – 8 (Must |
| Striping | be a multiple |
|
| of 2) |
30 | RAID 3 and | 6 – 32 (Must |
| Striping | be a multiple |
|
| of arrays) |
|
|
|
50 | RAID 5 and | 6 – 32 (Must |
| Striping | be a multiple |
|
| of arrays) |
|
|
|
(Number of disks) X (capacity of
smallest disk) / (2)
(Number of disks) X (capacity of smallest disk) – (capacity of 1 disk X number of Arrays)
(Number of disks) X (capacity of smallest disk) – (capacity of 1 disk X number of Arrays)
Cont’d
46ADAC Ultra2 S466 Hardware Guide