Best 20TB NAS hard drives
20TB sits near the top of the capacity ladder - for when you want the most storage a single bay can hold. Every pick is CMR, NAS- or enterprise-rated and helium-sealed, ranked by measured failure rate. Budget for long rebuilds and double-parity redundancy.
| Drive | Capacity | Tech | Class | Interface | AFR | €/TB | Price | |
|---|---|---|---|---|---|---|---|---|
| 1 |
MG10ACA20TE
Toshiba MG10
|
20 TB | CMR | Enterprise | SATA | 0.59% | €43.30 | €866 |
| 2 |
WD201KFGX
WD Red Pro
|
20 TB | CMR | NAS-Pro | SATA | - | €45.00 | €900 |
| 3 |
WD202KRYZ
WD Gold
|
20 TB | CMR | Enterprise | SATA | - | - | - |
| 4 |
WUH722020BLE6L4
WD Ultrastar DC HC560
|
20 TB | CMR | Enterprise | SATA | - | €51.64 | €1,033 |
| 5 |
ST20000NT001
Seagate IronWolf Pro
|
20 TB | CMR | NAS-Pro | SATA | - | €36.50 | €730 |
| 6 |
ST20000NM007D
Seagate Exos X20
|
20 TB | CMR | Enterprise | SATA | - | €34.55 | €691 |
Ranked by measured failure rate (Backblaze AFR). $/TB shows once live prices are wired.
Why 20TB
Maximum capacity per bay, for dense arrays and full enclosures where adding drives isn't an option. Nearly every 20TB drive is helium-sealed, so despite the size they run cooler and draw less power than you'd expect.
The trade-offs
Two of them, and both matter. You pay a per-terabyte premium at the top of the range, so check the $/TB against a 16TB drive before committing - the density is only worth it if you're genuinely out of bays. And rebuilds are long enough that double parity stops being optional: run RAID 6 / SHR-2 with any group of large drives. Size the build first with the storage planner.
Frequently asked questions
- Do I need RAID 6 with 20TB drives?
- Strongly recommended once you run more than a few. A 20TB rebuild can take a day or more; during that time a single-parity (RAID 5) array has no protection left. Double parity (RAID 6 / SHR-2) covers a second failure.
- Are 20TB drives worth it over 16TB?
- Only if you need the density or have limited bays. The largest drives usually carry a price-per-terabyte premium - check the per-TB value before paying for the biggest tier.