The following three models did not have a single failure in the first quarter of 2026. Note that the calculation is limited to models with more than 100 units and a total of more than 10,000 operating days per quarter.
Brand Model name Capacity (TB) Quantity Average number of operating months Total number of operating days Number of failures AFR (%) HGST HMS5C4040BLE640 4 186 106.1 15,858 0 0 HGST HUH728080ALE600 8 1026 93 86,921 0 0 HGST HUH721212ALE600 12 2608 75.4 234,350 8 1.25 HGST HUH721212ALE604 12 13,277 56.5 1,183,774 86 2.65 HGST HUH721212ALN604 12 9780 80.9 870,252 95 3.98 Seagate ST8000DM002 8 8910 112.3 639,473 25 1.43 Seagate ST8000NM000A 8 247 37.9 21,552 1 1.69 Seagate ST8000NM0055 8 13,232 101.5 1,176,619 39 1.21 Seagate ST10000NM0086 10 981 98.3 86,667 11 4.63 Seagate ST12000NM0007 12 983 75.8 87,389 11 4.59 Seagate ST12000NM0008 12 18,650 70.7 1,664,558 129 2.83 Seagate ST12000NM000J 12 1087 19 96,887 1 0.38 Seagate ST12000NM001G 12 13,216 60.7 1,185,545 33 1.02 Seagate ST14000NM000J 14 433 16.2 37,258 1 0.98 Seagate ST14000NM001G 14 10,519 60.3 944,400 21 0.81 Seagate ST14000NM0138 14 1251 62.6 111,709 15 4.9 Seagate ST16000NM000J 16 129 17 10,117 1 3.61 Seagate ST16000NM001G 16 34,729 41.2 3,098,105 44 0.52 Seagate ST16000NM002J 16 466 38.8 41,931 0 0 Seagate ST24000NM002H 24 9605 9.3 820,000 74 3.29 Toshiba MG07ACA14TA 14 37,263 64.1 3,343,724 94 1.03 Toshiba MG07ACA14TEY 14 996 39.8 88,602 5 2.06 Toshiba MG08ACA16TA 16 40,036 30.7 3,548,250 102 1.05 Toshiba MG08ACA16TE 16 6264 48.9 553,878 21 1.38 Toshiba MG08ACA16TEY 16 4885 50.5 435,063 26 2.18 Toshiba MG09ACA16TE 16 506 6.6 36,988 1 0.99 Toshiba MG10ACA20TE 20 20,451 11.6 1,665,263 42 0.92 Toshiba MG11ACA24TE 24 7203 4 495,387 3 0.22 WDC WUH721414ALE6L4 14 8640 61.3 776,557 7 0.33 WDC WUH721816ALE6L0 16 2994 50.4 267,868 24 3.27 WDC WUH721816ALE6L4 16 26,801 34.6 2,402,732 64 0.97 WDC WUH722222ALE6L4 22 45,638 16.1 3,992,942 42 0.38 WDC WUH722626ALE6L4 26 3604 2.5 182,471 4 0.8 Total - - - - 30,203,180 1030 1.24
Quarterly failure rate by model The target period is from January 1, 2026 to March 31, 2026, and the calculation target is models with more than 100 units and total operating days of more than 10,000 days as of March 31, 2026 (provided by Backblaze)
Five models had only one failure. Seagate "ST8000NM000A" (8TB), Seagate "ST12000NM000J" (12TB), Seagate "ST14000NM000J" (14TB), Seagate "ST16000NM000J" (16TB), and Toshiba "MG09ACA16TE" (16TB).
However, a small number of failures does not mean a low failure rate. Seagate "ST16000NM000J" has only 129 units left in operation, so one failure caused the AFR to rise to 3.61%. The smaller the number of units operated by a model, the greater the difference in failure rate with just one failure.
No new models were added in the first quarter of 2026. According to Backblaze, new models have been added in six of the last eight quarters, and a quarter without an addition is rare. On the other hand, capacity continues to increase. The company installed 10,220 units in the most recent quarter, of which 9,404 had a capacity of over 20TB. Although HDDs larger than 20TB have a short operating life, their AFR as a group remains at 0.85%.
The total failure rate (lifetime AFR) was 1.39%. Three new models have been added to the lifetime failure rate tally: Toshiba "MG09ACA16TE" (16TB), WDC "WUH722222ALE6L4" (22TB), and WDC "WUH722626ALE6L4" (26TB). The 4TB model, which has been in use for a long time, fell below the tally standard. HGST "HMS5C4040BLE640" has finished operating, and only 186 HGST "HMS5C4040BLE640" units remain.
Why you can't count "breakdown on the first day"
Backblaze has now confirmed that it has noticed unusual behavior in certain models. The cause was two types of mechanical problems. One affects writing, and the other affects when the power is turned on and off repeatedly. The company reduced the frequency of turning the power on and off to limit the impact, and put the system containing the affected HDD in a state where it could no longer accept new uploads, putting it in reserve.
During the course of this investigation, the limitations of the aggregation method itself became clear. The Drive Stats program records a HDD as failed if it was present the day before but stops responding on the same day. Under this condition, an HDD that fails on the first day of operation cannot be counted as a failure.
Backblaze acknowledged that it likely has historically underreported first-day failures. However, because the devices go through a screening process before being put into the data center, failures on the first day are rare.
