How long does it take to rebuild an 8TB drive in a NAS?
As a theoretical floor, an 8TB drive read or written flat-out at 180–280 MB/s sustained takes roughly 8–12 hours. Real rebuilds run longer: parity computation, concurrent use and throttling add time, and an SMR drive can multiply it. Start promptly, keep load light and use CMR drives.
Last verified July 22, 2026 · 2 official sources checked Updated
This is a floor, not a promise: it assumes the drive reads or writes flat-out at the rate you set, with nothing else happening. Real rebuilds run longer: parity computation, using the NAS during the rebuild, and drive throttling all add time, and an SMR drive can multiply it. Sustained rates for current 3.5-inch NAS drives run roughly 180–280 MB/s (see each drive’s datasheet); 200 MB/s is a reasonable middle default.
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The honest answer is a range: here is the floor from the arithmetic, then the reasons reality is slower.
The theoretical floor
A rebuild reads or writes across the whole drive, so capacity ÷ sustained transfer rate is the fastest it could possibly finish. Current 3.5-inch NAS drives publish sustained rates of roughly 180–280 MB/s. An 8 TB drive: 8,000,000 MB ÷ (180–280 MB/s) ≈ 8–12 hours as a floor. Adjust the rate in the estimator above for your specific drive.
Why real rebuilds run longer
- Parity computation adds work beyond a flat copy.
- Using the NAS during the rebuild slows it.
- Throttling keeps the array responsive at the cost of speed.
- SMR drives can multiply the time or stall.
Why it matters
A single-parity array has no fault tolerance during the rebuild, so a second failure loses the pool. Start immediately, keep load light, use CMR, and consider RAID 6 / SHR-2 on larger arrays. The table lists in-stock 8 TB CMR drives by price per terabyte.
8 TB CMR drives, by CA$/TB
Live Amazon.ca prices in CAD, ranked by price per terabyte. The Recording column is verified against manufacturer documentation. Prices checked
| Model | Capacity | Recording | Price | CA$/raw TB | |
|---|---|---|---|---|---|
 Toshiba N300 PRO 8TB Large-Sized Business NAS (up to 24 Bays) 3.5-Inch Internal Hard Drive - Up to 300 TB/Year Workload Rate CMR SATA 6 GB/s 7200 RPM 512 MB Cache - HDWG780XZSTBNewbest price per TB CMR recording, SATA NAS drive rated for 24/7 use Amazon.ca · sold by HYPER MEGA Electronics · one bare internal drive; shipping and taxes not included · checked Oct 7, 2026CA$480Buy on Amazon | 8 TB | CMR ✓ | CA$480 | CA$60.00/TB | Buy on Amazon |
 Western Digital 8TB WD Red Plus NAS Internal Hard Drive HDD - 5640 RPM, SATA 6 Gb/s, CMR, 256 MB Cache, 3.5" - WD80EFPXNew CMR recording, SATA NAS drive rated for 24/7 use Amazon.ca · sold by Amazon.ca · one bare internal drive; shipping and taxes not included · checked Oct 7, 2026CA$530Buy on Amazon | 8 TB | CMR ✓ | CA$530 | CA$66.25/TB | Buy on Amazon |
 Seagate IronWolf Pro 3.5" 8TB HDD with Data Recovery Service 5 Year Warranty 256MB 7200rpm 24 Hours Service for PC NAS RV Sensor ST8000NE001New CMR recording, SATA NAS drive rated for 24/7 use Amazon.ca · sold by Deals2You · one bare internal drive; shipping and taxes not included · checked Oct 7, 2026CA$559Buy on Amazon | 8 TB | CMR ✓ | CA$559 | CA$69.88/TB | Buy on Amazon |
 WD Ultrastar DC HA340 WUS721208BLE6L4 Hard Drive Data Centre 8 TB Internal 3.5 Inch SATA 6Gb/s 7200 RPM Buffer: 256 MBNew CMR recording, SATA enterprise drive Amazon.ca · sold by Amazon US · one bare internal drive; shipping and taxes not included · checked Oct 7, 2026 · ships from the US through Amazon.caCA$671Buy on Amazon | 8 TB | CMR ✓ | CA$671 | CA$83.92/TB | Buy on Amazon |
 Western Digital 8TB Ultrastar DC HC320 SATA HDD - 7200 RPM Class, SATA 6 Gb/s, 256MB Cache, 3.5" - HUS728T8TALE6L4New CMR recording, SATA enterprise drive Amazon.ca · sold by Amazon US · one bare internal drive; shipping and taxes not included · checked Oct 7, 2026 · ships from the US through Amazon.caCA$738Buy on Amazon | 8 TB | CMR ✓ | CA$738 | CA$92.30/TB | Buy on Amazon |
 Western Digital WD Red Plus Internal Hard Drive 8TB CMR 3.5 inch SATA 5640 RPM 256MB NAS WD80EFPX-AJP Eco PackageNew CMR recording, SATA NAS drive rated for 24/7 use Amazon.ca · sold by Amazon US · one bare internal drive; shipping and taxes not included · checked Oct 7, 2026 · ships from the US through Amazon.caCA$759Buy on Amazon | 8 TB | CMR ✓ | CA$759 | CA$94.86/TB | Buy on Amazon |
 Seagate IronWolf ST8000VN002 - hard drive - 8 TB - SATA 6Gb/sNew CMR recording, SATA NAS drive rated for 24/7 use Amazon.ca · sold by Rarewaves-CA · one bare internal drive; shipping and taxes not included · checked Oct 7, 2026CA$766Buy on Amazon | 8 TB | CMR ✓ | CA$766 | CA$95.77/TB | Buy on Amazon |
 Toshiba 8.9cm (3.5") 8TB SATA3 NAS N300 7200RPM Intern BulkNew CMR recording, SATA NAS drive rated for 24/7 use Amazon.ca · sold by Rarewaves-CA · one bare internal drive; shipping and taxes not included · checked Oct 7, 2026CA$816Buy on Amazon | 8 TB | CMR ✓ | CA$816 | CA$101.95/TB | Buy on Amazon |
 Seagate Ironwolf ST8000VN002-TD 3.5" (RV Sensor) 8 TB Internal Hard Drive (CMR) 3 Year Warranty 24 Hour Operation for PC NASNew CMR recording, SATA NAS drive rated for 24/7 use Amazon.ca · sold by Wish Fulfillment · one bare internal drive; shipping and taxes not included · checked Oct 7, 2026CA$1,031Buy on Amazon | 8 TB | CMR ✓ | CA$1,031 | CA$128.84/TB | Buy on Amazon |
Related questions
Sources
Every technical claim on this page is checked against manufacturer and standards documentation. Dates are when each source was last reviewed.
- Seagate: IronWolf Pro datasheet (Max Sustained Transfer Rate OD, up to ~285 MB/s) (checked 2026-07-22)
- Synology KB: Repair a Storage Pool (checked 2026-07-22)