In May 2016, the folks at Backblaze published an excellent report on the durability of the hard drives used in their servers. That report offered a preview of what 2016 might bring, but now that the year has come to a close, they have updated their statistics with more complete numbers. This update was necessary because the company acquired a significant number of 6 and 8 TB drives while retiring smaller units.
Buying a hard drive remains one of the most delicate decisions in the computer market. With only four players, one might think there isn't much to choose from, but even within the same brand there can be huge differences. The problem with hard drives is that there's usually no middle ground in their failures. SMART indicators and the appearance of bad sectors are powerful signals, but the average user discovers the situation when it's already too late. For that and many other reasons, we always value studies focused on multiple brands and models. Backblaze has become an excellent reference thanks to its more than 71,000 drives and its annual statistics.
The 2016 Numbers
What happened in 2016? Information from the first quarter was published in our previous article, but today we have the complete failure data for that year. From a global perspective, the company used 71,939 drives dedicated to data (the physical total was 73,653 drives), of which only 1,225 failed. That translates to a failure rate below two percent, confirming that the percentages of all companies are declining (6.39 percent in 2014, and 2.47 percent in 2015). By brand, Western Digital tops the list with 3.88 percent (1,626 units), followed by Seagate with 2.65 percent (45,531 units) and Toshiba with 1.27 percent (237 units). The HGST division of Western Digital again showed impressive durability: with 24,545 drives, Backblaze recorded only 132 failures in 2016, a mere 0.6 percent.
Failures by Capacity
Another interesting aspect is the failure rate by drive size. According to their report, the majority of drives that ran in Backblaze during 2016 were 4 TB (76 percent), but new 8 TB units also arrived, now making up 12 percent. Failure rates by size were very even: only one of their 45 5 TB drives failed in 2016, but that was enough to put them on top with 2.22 percent. 4 TB drives recorded a rate of 2.06 percent, and 6 TB drives came in at 1.76 percent. It's a good start for 8 TB drives (1.6 percent) and surprising resistance from 3 TB models (1.4 percent).
Model-by-Model Breakdown
To finish, let's look at the failure rates for specific models. Three of them remained undefeated: HGST HUH728080ALE600 (8 TB), Seagate ST8000NM0055 (8 TB), and Toshiba MD04ABA400V (4 TB), but these are few units and have a fairly young average age. The real stars are the HGST 4 TB drives: in just over 19,000 units, only 76 failed. The two most worrying figures belong to the WD60EFRX of the WD Red series with 6 TB and 5,400 RPM, which failed in 5.49 percent of cases, and the Seagate Barracuda ST4000DX000, which already had a bad track record and closed the year at 13.57 percent. In summary: HGST remains the most robust option for this very demanding environment, and the 8 TB drives improved greatly.
