Selecting a RAID Level
Level | Description and | Pros | Cons | Maximum | Fault |
| Use |
|
| Physical | Tolerant |
|
|
|
| Drives |
|
0 | Data divided in | High data | No fault | One to 15 | No |
| blocks and | throughput | tolerance. All |
|
|
| distributed | for large | data lost if |
|
|
| sequentially (pure | files | any drive |
|
|
| striping). Use for |
| fails. |
|
|
|
|
|
|
| |
| that requires high |
|
|
|
|
| performance. |
|
|
|
|
1 | Data duplicated on | 100% data | Doubles disk | 2 | Yes |
| another disk | redundancy | space. |
|
|
| (mirroring). Use |
| Reduced |
|
|
| for |
| performance |
|
|
|
| during |
|
| |
| systems. |
| rebuilds. |
|
|
3 | Disk striping with a | Achieves | Performance | Three to 15 | Yes |
| dedicated parity | data | not as good as |
|
|
| drive. Use for non- | redundancy | RAID 1 |
|
|
| interactive apps | at low cost |
|
|
|
| that process large |
|
|
|
|
| files sequentially. |
|
|
|
|
5 | Disk striping and | Achieves | Performance | Three to 15 | Yes |
| parity data across | data | not as good as |
|
|
| all drives. Use for | redundancy | RAID 1 |
|
|
| high read volume | at low cost |
|
|
|
| but low write |
|
|
|
|
| volume, such as |
|
|
|
|
| transaction |
|
|
|
|
| processing. |
|
|
|
|
10 | Data striping and | High data | More | Four to 14 | Yes |
| mirrored drives. | transfers, | complicated | (must be a |
|
|
| complete |
| multiple of |
|
|
| redundancy |
| two) |
|
30 | Disk striping with a | High data | More | Six to15 | Yes |
| dedicated parity | transfers, | complicated |
|
|
| drive. | redundancy |
|
|
|
50 | Disk striping and | High data | More | Six to 15 | Yes |
| parity data across | transfers, | complicated |
|
|
| all drives. | redundancy |
|
|
|
Note: The maximum number of physical drives supported by the Express 500 controller is 15.
18MegaRAID Express 500 Hardware Guide