Uses | Provides high data throughput, especially for large files. Use |
| RAID 5 for transaction processing applications, because each |
| drive can read and write independently. If a drive fails, the |
| MegaRAID SCSI |
| missing information. Use also for office automation and online |
| customer service that requires fault tolerance. Use for any |
| application that has high read request rates but low write |
| request rates. |
|
|
Strong Points | Provides data redundancy and good performance in most |
| environments |
|
|
Weak Points | Disk drive performance is reduced if a drive is being rebuilt. |
| Environments with few processes do not perform as well |
| because the RAID overhead is not offset by the performance |
| gains in handling simultaneous processes. |
|
|
Drives | 3 to 30 |
| The MegaRAID SCSI |
| SCSI channels, with up to 15 SCSI devices on each channel. |
|
|
Figure 3.3 shows a RAID 5 array with six disk drives.
Figure 3.3 RAID 5 ArrayMegaRAID Controller
Note: Parity is distributed |
|
across drives in the array. | Data Flow |
|
Disk 1 | Disk 2 | Disk 3 | Disk 4 | Disk 5 | Disk 6 |
Segment 1 | Segment 2 | Segment 3 | Segment 4 | Segment 5 | Segment 6 |
Segment 7 | Segment 8 | Segment 9 | Segment 10 | Segment 11 | Segment 12 |
Parity |
| Parity |
| Parity |
|
RAID 5 |
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