DiskGradeHard drive reliability grades
Hard drives and SSDs graded A to F on how often they really fail. 69 models, 1,124,223 drive-years, 17,073 failures, Q1 2023 to Q3 2026. Average failure rate: 1.52% a year. Click a column heading to sort.
4 TB8 TB10 TB12 TB14 TB16 TB24 TB
HGSTSeagateToshibaWestern Digital
Hard drives
| Grade | Model | Type | Size | Failure rate / year | Drives in use | Drive-years | Failures |
|---|---|---|---|---|---|---|---|
| A | HGST HMS5C4040BLE640 | HDD | 4 TB | 0.32% | 0 (retired) | 21,067 | 67 |
| A | Seagate ST8000NM000A | HDD | 8 TB | 0.37% | 229 | 806 | 3 |
| A | HGST HMS5C4040ALE640 | HDD | 4 TB | 0.38% | 0 (retired) | 4,207 | 16 |
| A | Seagate ST6000DX000 | HDD | 6 TB | 0.52% | 0 (retired) | 1,147 | 6 |
| A | Toshiba MG11ACA24TE | HDD | 24 TB | 0.52% | 16,556 | 7,816 | 41 |
| A | Western Digital WUH722222ALE6L4 | HDD | 22 TB | 0.54% | 50,132 | 85,125 | 456 |
| A | Seagate ST16000NM002J | HDD | 16 TB | 0.56% | 463 | 1,607 | 9 |
| B | Western Digital WUH721816ALE6L4 | HDD | 16 TB | 0.60% | 26,751 | 87,781 | 529 |
| B | Seagate ST16000NM001G | HDD | 16 TB | 0.62% | 35,594 | 117,216 | 725 |
| B | Western Digital WUH721414ALE6L4 | HDD | 14 TB | 0.71% | 8,522 | 31,964 | 226 |
| B | Toshiba MG10ACA20TE | HDD | 20 TB | 0.83% | 29,873 | 32,421 | 268 |
| B | HGST HUH721212ALE600 | HDD | 12 TB | 0.90% | 2,590 | 9,719 | 87 |
| B | Western Digital WUH722626ALE6L4 | HDD | 26 TB | 0.92% | 7,021 | 3,793 | 35 |
| B | Seagate ST12000NM000J | HDD | 12 TB | 0.97% | 1,067 | 2,271 | 22 |
| B | Toshiba MG08ACA16TA | HDD | 16 TB | 1.03% | 38,772 | 121,800 | 1,260 |
| B | Seagate ST12000NM001G | HDD | 12 TB | 1.13% | 13,006 | 49,098 | 553 |
| B | Toshiba MG08ACA16TE | HDD | 16 TB | 1.14% | 6,170 | 22,458 | 257 |
| B | Toshiba MG07ACA14TA | HDD | 14 TB | 1.15% | 36,697 | 140,978 | 1,620 |
| C | Seagate ST14000NM001G | HDD | 14 TB | 1.51% | 10,413 | 39,759 | 600 |
| C | Seagate ST14000NM000J | HDD | 14 TB | 1.56% | 497 | 835 | 13 |
| C | Toshiba MG07ACA14TEY | HDD | 14 TB | 1.70% | 965 | 2,944 | 50 |
| C | Toshiba MG09ACA16TE | HDD | 16 TB | 1.71% | 1,009 | 703 | 12 |
| C | Western Digital WUH721816ALE6L0 | HDD | 16 TB | 1.81% | 2,896 | 10,953 | 198 |
| D | Seagate ST8000DM002 | HDD | 8 TB | 2.15% | 5,927 | 32,297 | 694 |
| D | HGST HUH728080ALE600 | HDD | 8 TB | 2.39% | 101 | 3,554 | 85 |
| D | HGST HUH721212ALE604 | HDD | 12 TB | 2.40% | 12,885 | 49,399 | 1,184 |
| D | Seagate ST12000NM0008 | HDD | 12 TB | 2.78% | 17,915 | 71,422 | 1,986 |
| D | Seagate ST8000NM0055 | HDD | 8 TB | 2.85% | 12,700 | 50,867 | 1,449 |
| D | Toshiba MG08ACA16TEY | HDD | 16 TB | 2.91% | 4,767 | 19,015 | 554 |
| D | Seagate ST24000NM002H | HDD | 24 TB | 3.36% | 9,433 | 12,353 | 415 |
| D | Western Digital WD5000LPVX | HDD | 500 GB | 3.37% | 37 | 326 | 11 |
| D | Seagate ST4000DM000 | HDD | 4 TB | 3.46% | 0 (retired) | 20,249 | 701 |
| F | HGST HUH721212ALN604 | HDD | 12 TB | 4.60% | 9,328 | 37,997 | 1,747 |
| F | Seagate ST500LM030 | HDD | 500 GB | 5.05% | 144 | 673 | 34 |
| F | Seagate ST500LM012 HN | HDD | 500 GB | 5.40% | 50 | 648 | 35 |
| F | HGST HUH728080ALE604 | HDD | 8 TB | 5.53% | 68 | 308 | 17 |
| F | Seagate ST10000NM0086 | HDD | 10 TB | 5.80% | 934 | 3,914 | 227 |
| F | Seagate ST14000NM0138 | HDD | 14 TB | 6.22% | 1,159 | 5,003 | 311 |
| F | Seagate ST12000NM0007 | HDD | 12 TB | 7.88% | 931 | 4,021 | 317 |
| F | Toshiba MQ01ABF050 | HDD | 500 GB | 10.58% | 98 | 605 | 64 |
| F | Toshiba MQ01ABF050M | HDD | 500 GB | 11.53% | 86 | 590 | 68 |
SSDs
Mostly small boot drives in Backblaze's servers, so not directly comparable with the hard drives above.
| Grade | Model | Type | Size | Failure rate / year | Drives in use | Drive-years | Failures |
|---|---|---|---|---|---|---|---|
| A | Seagate IronWolf ZA250NM10002 | SSD | 250 GB | 0.00% | 201 | 510 | 0 |
| A | Dell DELLBOSS VD | SSD | 480 GB | 0.19% | 430 | 1,591 | 3 |
| A | Seagate BarraCuda 120 SSD ZA250CM10003 | SSD | 250 GB | 0.20% | 1,072 | 4,095 | 8 |
| A | Western Digital WDS250G2B0A | SSD | 250 GB | 0.35% | 170 | 576 | 2 |
| A | Crucial CT250MX500SSD1 | SSD | 250 GB | 0.36% | 683 | 2,475 | 9 |
| B | Micron MTFDDAV240TCB | SSD | 240 GB | 0.62% | 84 | 323 | 2 |
| B | Seagate BarraCuda SSD ZA250CM10002 | SSD | 250 GB | 0.74% | 458 | 1,889 | 14 |
| C | Seagate SSD | SSD | 250 GB | 1.33% | 97 | 377 | 5 |
| F | Western Digital Blue SA510 2.5 250GB | SSD | 250 GB | 4.80% | 140 | 417 | 20 |
Not graded: too little data
Fewer than 100,000 drive-days on record, so the failure rate is not dependable.
| Grade | Model | Type | Size | Failure rate / year | Drives in use | Drive-years | Failures |
|---|---|---|---|---|---|---|---|
| – | Seagate ST16000NM000J | HDD | 16 TB | 2.23% | 171 | 269 | 6 |
| – | Seagate ST14000NM0018 | HDD | 14 TB | 6.92% | 59 | 231 | 16 |
| – | Seagate ST18000NM000J | HDD | 18 TB | 2.19% | 68 | 229 | 5 |
| – | Toshiba HDWF180 | HDD | 8 TB | 4.95% | 47 | 202 | 10 |
| – | Western Digital WD5000LPCX | HDD | 500 GB | 1.12% | 33 | 179 | 2 |
| – | Seagate ST10000NM001G | HDD | 10 TB | 0.00% | 28 | 105 | 0 |
| – | Seagate ST500LM021 | HDD | 500 GB | 1.93% | 21 | 104 | 2 |
| – | Toshiba MD04ABA400V | HDD | 4 TB | 1.04% | 0 (retired) | 96 | 1 |
| – | Seagate ST16000NM005G | HDD | 16 TB | 0.00% | 25 | 94 | 0 |
| – | Seagate ST8000DM005 | HDD | 8 TB | 1.16% | 15 | 86 | 1 |
| – | HGST HUH721010ALE600 | HDD | 10 TB | 0.00% | 20 | 75 | 0 |
| – | HGST HUS728T8TALE6L4 | HDD | 8 TB | 1.39% | 18 | 72 | 1 |
| – | HGST HUS726040ALE610 | HDD | 4 TB | 0.00% | 0 (retired) | 53 | 0 |
| – | Seagate BarraCuda SSD ZA500CM10002 | SSD | 500 GB | 0.00% | 10 | 50 | 0 |
| – | Seagate ST12000NM003G | HDD | 12 TB | 0.00% | 27 | 47 | 0 |
| – | Seagate ST4000DM005 | HDD | 4 TB | 5.27% | 0 (retired) | 38 | 2 |
| – | Toshiba MG11ACA16TE | HDD | 16 TB | 0.00% | 76 | 34 | 0 |
| – | Seagate ST14000NM002J | HDD | 14 TB | 3.37% | 24 | 30 | 1 |
| – | Western Digital WD5000BPKT | HDD | 500 GB | 0.00% | 7 | 28 | 0 |