Backside line: A examine of Backblaze’s hard-drive fleet discovered that HGST and Western Digital drives had decrease failure charges than Seagate and Toshiba drives after accounting for elements resembling age, capability, working temperature, and kind issue. The outcomes present how uncooked fleetwide failure figures can obscure significant reliability variations when producers’ drives are at totally different levels of their service lives.
The peer-reviewed IEEE examine was written by Christoph Siemroth of the College of Essex and Yeomyung Park of Sungkyunkwan College. It reviewed knowledge on 443,156 drives utilized in Backblaze knowledge facilities from 2013 by the second quarter of 2025. The pattern lined greater than 1.66 million drive-years.
The researchers discovered that HGST drives failed at about 41% of Seagate’s charge in comparison below comparable situations. WD drives failed at about 52% of Seagate’s charge. Toshiba drives had a charge equal to 107% of Seagate’s charge.
HGST ranked first within the evaluation, though the model is now not offered as a separate new-drive possibility. Western Digital acquired HGST in 2012 and later phased out the model.
The examine takes a unique method from Backblaze’s common quarterly reliability stories, which examine the drives lively within the firm’s storage fleet at a given time. The authors mentioned that may produce uneven comparisons as a result of the fleets are usually not the identical age.
HGST accounted for a lot of new Backblaze installations in 2014. Seagate was the principle provider from 2015 by 2020. Toshiba had probably the most new installations in 2023, and WD led in 2024. Consequently, reported failure charges can examine outdated Seagate and HGST drives with newer Toshiba and WD fashions.
The researchers adjusted their evaluation to account for these variations. Additionally they excluded a number of the bias created when drives depart service earlier than they fail. About 146,943 drives, or 31% of the pattern, have been faraway from Backblaze’s dataset with no recorded failure. Most have been doubtless changed as the corporate moved to higher-capacity {hardware}.
Toshiba confirmed the clearest change in failure conduct as drives aged. Its month-to-month failure charge rose greater than fourfold after 60 months in service. From 50 to 100 months, Toshiba drives failed at a charge of 5 to 6 per 1,000 drives every month. The opposite three manufacturers typically remained at or under 2.5 failures per 1,000 drives per thirty days over that interval.
Seagate had the best failure charge amongst newer drives within the examine. However its charge didn’t improve as sharply with age as Toshiba’s did. Backblaze has beforehand reported that many drive failures happen earlier than a drive has been in operation for 3 years.
Working temperature additionally mattered. The examine discovered that every 1-degree Celsius improve in common drive temperature raised the failure charge by 2.1%. A ten-degree Celsius improve would increase the speed by about 23% when compounded.
Greater-capacity drives carried out higher within the mannequin. Every extra terabyte of capability was linked to a 3.4% decline in failure charges. The researchers mentioned that could be partly tied to newer drive designs, together with helium-filled enclosures and advances in head manufacturing.
The outcomes don’t essentially apply to exhausting drives utilized in client PCs or dwelling storage techniques. Backblaze operates enterprise drives in data-center situations, and the dataset doesn’t embody comparable workload knowledge for every producer.
The evaluation can be weighted towards shorter service durations. Solely 0.52% of drives within the examine stayed in operation for greater than 10 years. That makes the outcomes extra helpful for evaluating reliability throughout a drive’s early and center years than for estimating its full lifespan.
WD and HGST completed shut collectively within the adjusted rating. The authors mentioned that would replicate expertise sharing after WD acquired HGST. Backblaze’s most up-to-date annual report put the corporate’s general annualized drive failure charge at 1.36% in 2025.