系统内冗余或重复数据的度量，表明存储和潜在性能问题效率低下。
1 RD = 0.5 PB
1 PB = 2 RD
例子:
将15 冗余数据转换为奇偶校验的冗余：
15 RD = 7.5 PB
| 冗余数据 | 奇偶校验的冗余 |
|---|---|
| 0.01 RD | 0.005 PB |
| 0.1 RD | 0.05 PB |
| 1 RD | 0.5 PB |
| 2 RD | 1 PB |
| 3 RD | 1.5 PB |
| 5 RD | 2.5 PB |
| 10 RD | 5 PB |
| 20 RD | 10 PB |
| 30 RD | 15 PB |
| 40 RD | 20 PB |
| 50 RD | 25 PB |
| 60 RD | 30 PB |
| 70 RD | 35 PB |
| 80 RD | 40 PB |
| 90 RD | 45 PB |
| 100 RD | 50 PB |
| 250 RD | 125 PB |
| 500 RD | 250 PB |
| 750 RD | 375 PB |
| 1000 RD | 500 PB |
| 10000 RD | 5,000 PB |
| 100000 RD | 50,000 PB |
规则