Storage Array Rebuild Time Calculator
Estimate a replacement drive’s rebuild time and I/O volume from capacity, copied fraction, aggregate throughput and foreground reserve.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Calculate replacement bytes written, reduce entered aggregate throughput by the foreground reserve and divide to estimate duration. Report source reads separately.
Time=capacity×copied fraction/[aggregate byte rate×(1−reserve)]; source reads=written bytes×read multiplier
Worked example
4 decimal TB at 200 MB/s aggregate replacement writes, with 25% reserved, gives 150 MB/s effective and about 7.4074 hours. A read multiplier of 2 gives 8 TB source reads.
Assumptions and input details
Entered throughput is already the aggregate target-write rate after topology limitations; the source-read multiplier is not a second throughput penalty. A full rebuild may require the whole drive even if files occupy less space. The copied fraction must match actual controller behavior. No bad sectors, retries, changing rates, verification passes or failure probabilities are predicted. Units distinguish decimal TB from binary TiB.
Unit definitions
Unit selection is independent of language. Each selector contains only units for its physical quantity. Calculations use defined base units internally.
One byte is eight bits. Decimal prefixes (k, M, G, T, P, E) use powers of 1000. Binary prefixes (Ki, Mi, Gi, Ti, Pi, Ei) use powers of 1024. Transfer rates are per second.
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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