B-RAID Level Comparison Table
Appendix B: RAID Level Comparison Table
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RAID | Description |
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| Min. | Max. | Capacity | Data |
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| I/O |
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Level |
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| Drives | Drives |
| Reliability |
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| Transfer Rate |
| Request Rates |
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Span | Also known as disk spanning. Data | 1 | 4 | (N) | No data protection |
| Same as a single disk | same as a single disk |
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| is distributed sequentially to all |
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| drives. There is no data protection. |
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0 | Also known as striping |
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| 1 | 4 | (N) | No data |
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| Very High |
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| Very High for |
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| Data | distributed | across | multiple |
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| Both Reads and Writes | |||||||
| drives in the array simultaneously. |
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| There is no data protection |
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1 | Also known as mirroring |
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| 2 | 4 | 1/(N ) | Lower than | RAID | 6, | Reads are higher |
| Reads | are | twice | faster | |||||||
| All data replicated on N Separated |
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| Disks | Higher than RAID 5 |
| Than a single disk; |
| than a single disk; |
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| disks. N is always a multiple of 2. |
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| This is a high availability Solution, |
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| Writes similar to a sin- | Write | are similar | to | a | ||||||||||
| but due to the 100% data duplication, |
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| gle disk |
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| single disk. |
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| it is also a costly solution. |
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10 | Also known as striped mirroring. Data | 4 | 4 | 1/2 (N) | Lower than | RAID | 6, | Reads | are | similar | to | Reads | are | similar | to | |||||||
| and parity information is subdivided |
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| Disks | higher than RAID 5 |
| RAID 0 |
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| RAID 0 |
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| and distributed across all disks. This |
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| is a high availability Solution, but |
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| Writes | are | similar | to | Writes are similar to sin- | ||||||||||
| due to the 100% data duplication, it |
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| single disk |
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| gle disk |
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| is also a costly solution. |
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5 | Also | known | 3 | 5 | Lower than RAID 1, 10 | Reads are similar to |
| Reads are similar to |
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| distributed Parity. Data and parity |
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| Disks |
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| RAID 0; |
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| RAID 0; |
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| information | is | subdivided | and |
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| Higher than | a single |
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| distributed across all disk. Parity |
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| Writes are slower than | Writes are slower than a | |||||||||||||
| must be the equal to the smallest |
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| RAID 0 |
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| single disk. |
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| disk capacity in the array. Parity |
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| information normally stored on a |
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| dedicated parity disk. |
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6 | Also known as dual parity. Similar | 4 | 5 | Highest Reliability |
| Reads are similar to |
| Reads are similar to |
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| to RAID 5, but does two different |
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| Disks) |
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| RAID 0; |
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| RAID 0; |
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| parity computations or the same |
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| computation on overlapping subsets |
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| Writes are slower than | Writes are slower than a | |||||||||||||
| of the data. The RAID 6 can offer |
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| RAID 5 |
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| single disk. |
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| fault | tolerance | greater that | RAID |
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| 1 or RAID 5 but only consumes |
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| the capacity of 2 disk drives for |
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| distributed | parity | data | reliability |
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| similar to RAID 0. |
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MaxNAS Owner’s Manual | 60 |
