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 |
| parity data to recreate all 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 |
|
|
Figure 3.3 shows a RAID 5 array with six disk drives.
Figure 3.3 RAID 5 Array
MegaRAID 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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