Though Backblaze doesn't have many of these units (only 131), limiting the value of the data, the company found that almost 10 percent of the disks failed, even though their average age is just shy of nine months. The standout here, for all the wrong reasons, is the company's 2TB units. The weakest performance was from Western Digital. Although the failure rates are a bit higher than those of the HGST spindles, Backblaze has standardized on 4TB Seagate disks thanks to a combination of price and availability. With these troublesome disks removed, the remaining Seagate disks, both 4TB and 6TB, fared much better. The third problematic Seagate model, a 3TB drive, has also been retired after showing a cumulative failure rate of 28.34 percent. The other model, now averaging about five years old, still has a high failure rate of 10.16 percent. One of those models has since been retired, for a lifetime cumulative failure rate of 23.86 percent. Two of the models that performed so badly in 2014 are 1.5TB drives. Seagate showed much stronger performance, too. Over the last two and a half years, only 1.55 percent of them have failed. The HGST drives are some of the oldest in Backblaze's collection, with the 2TB units being almost five years old on average. Across all the HGST models that Backblaze used (one 2TB, two 3TB, three 4TB, and one 8TB), failure rates were low across the board. Some Seagate models, on the other hand, showed alarming unreliability and extremely high failure rates.įor 2015, HGST maintained its strong performance. In 2014, HGST was the standout performer, with all its models showing extremely good reliability. Cloud backup provider Backblaze has published more of its hard drive reliability data, giving a look at the company's experiences with its 56,224 hard disks in 2015.