Summary of RAID Methods
RAID 0 | RAID 1 | RAID1+0 | RAID 5 | RAID ADG | |
---|---|---|---|---|---|
Alternative name | Striping (no fault tolerance) | Mirroring | Mirroring and Striping | Distributed Data Guarding | Advanced Data Guarding |
Usable disk space* | 100% | 50% | 50% | 67% to 96% | 50% to 93% |
Usable disk space formula | n | n/2 | n/2 | (n-1)/n | (n-2)/n |
Minimum number of physical disks | 1 | 2 | 4 | 3 | 4 |
Tolerates failure of one physical disk? | No | Yes | Yes | Yes | Yes |
Tolerates simultaneous failure of more than one physical disk? | No | No | Only if no two failed disks are in a mirrored pair | No | Yes |
Read performance | High | High | High | High | High |
Write performance | High | Medium | Medium | Low | Low |
Relative cost | Low | High | High | Medium | Medium |
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