Best NAS hard drives for Unraid
Unraid writes to independent drives guarded by a dedicated parity disk. That parity drive takes heavy, sustained writes, so it has to be CMR - an SMR parity drive can crawl and stall a rebuild. Data drives should be CMR too. Every pick below is CMR, ranked by measured failure rate.
| Drive | Capacity | Tech | Class | Interface | AFR | €/TB | Price | |
|---|---|---|---|---|---|---|---|---|
| 1 |
ST16000NM000J
Seagate Exos X18
|
16 TB | CMR | Enterprise | SATA | 0.22% | €27.49 | €440 |
| 2 |
WUH722626ALE6L4
WD Ultrastar DC HC590
|
26 TB | CMR | Enterprise | SATA | 0.40% | €41.42 | €1,077 |
| 3 |
WUH722222ALE6L4
WD Ultrastar DC HC570
|
22 TB | CMR | Enterprise | SATA | 0.47% | €51.11 | €1,124 |
| 4 |
ST16000NM001G
Seagate Exos X16
|
16 TB | CMR | Enterprise | SATA | 0.54% | €31.16 | €499 |
| 5 |
MG10ACA20TE
Toshiba MG10
|
20 TB | CMR | Enterprise | SATA | 0.59% | €43.30 | €866 |
| 6 |
MG11ACA24TE
Toshiba MG11
|
24 TB | CMR | Enterprise | SATA | 0.68% | €42.38 | €1,017 |
| 7 |
WUH721816ALE6Lx
WD Ultrastar DC HC550
|
16 TB | CMR | Enterprise | SATA | 0.80% | €41.25 | €660 |
| 8 |
WUH721414ALE6L4
WD Ultrastar DC HC530
|
14 TB | CMR | Enterprise | SATA | 0.81% | - | - |
| 9 |
ST12000NM001G
Seagate Exos X16
|
12 TB | CMR | Enterprise | SATA | 0.96% | €36.77 | €441 |
| 10 |
MG07ACA14TE
Toshiba MG07
|
14 TB | CMR | Enterprise | SATA | 1.18% | - | - |
| 11 |
ST14000NM001G
Seagate Exos X16
|
14 TB | CMR | Enterprise | SATA | 1.35% | €32.14 | €450 |
| 12 |
MG08ACA16Tx
Toshiba MG08
|
16 TB | CMR | Enterprise | SATA | 1.48% | €27.49 | €440 |
Ranked by measured failure rate (Backblaze AFR). $/TB shows once live prices are wired.
The parity drive: CMR, and the largest
Parity is where Unraid is strictest. It absorbs continuous writes during normal use and is written end to end during every rebuild, so it must be a CMR drive and at least as large as your biggest data disk. A lot of builders buy the largest drive they'll ever use as parity first, then add smaller data drives under it.
Data drives
Normal writes hit one data drive at a time, fairly sequentially - gentler than a striped array - but a rebuild still reads every disk, so CMR is the safe call across the board. Unraid's real perk is mixing capacities freely, so buy whatever's best value per terabyte (as long as parity stays the largest). Size it out with the storage planner.
Frequently asked questions
- Can I use SMR drives in Unraid?
- Not recommended - and never for the parity drive. A parity rebuild writes the entire disk; SMR drives slow drastically and can stall it. Use CMR throughout. See our note on SMR and Unraid for detail.
- Does the parity drive need to be the largest?
- Yes - the parity drive must be at least as large as your biggest data drive. Many Unraid users buy the largest drive they plan to use as parity first.
- Can I mix drive sizes in Unraid?
- Yes - that's a strength of Unraid. Each data drive is independent, so you can mix capacities freely (as long as parity is the largest). Stick to CMR for all of them.