RAID Capacity Calculator
Enter disk count and size. Compare usable capacity, redundancy and overhead.
Inputs
Reserved hot spares are not counted in usable capacity.
Results
Usable capacity
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Redundancy
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Overhead
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Min required
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Formula & assumptions
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Notes
- Calculator assumes identical drive sizes and RAID sets on a single controller.
- Hot spares do not contribute to capacity and are subtracted from the drive count.
- Real-world capacity can be a bit lower due to filesystem metadata, striping, and vendor rounding.
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