Backblaze, a cloud storage company, records the reliability of different hard drives from different suppliers. The 2015 numbers reveal the success of the 4TB Seagate ST4000DM000, of which Backblaze now owns almost 30,000.

Here's a surprise: Seagate hard drives may now be more reliable than Western Digital models, according to Backblaze's Hard Drive Reliability Review for 2015. The failure rates in the bar chart above are cumulative from April 2013 to the end of 2015, by which time the company had 56,224 hard drives containing customer data in 1,249 Backblaze Storage Pods.

Previously, some Seagate hard drives exhibited high failure rates, with almost a third of Backblaze's 3TB Seagate drives (ST3000DM001) failing in 2012. In September 2014, I reported that "the three least reliable drives tested are all Seagate Barracuda models. The Seagate Barracuda 7200.11 has had an annual failure rate of 24.9 percent, the 3TB 7200.14 of 15.7 percent, and the 1.5TB Barracuda LP of 9.6 percent." (See Who makes the most reliable hard disk drives? Backblaze has updated its stats)

As Robin Harris reported here in April, Backblaze eventually pulled the 3TB Seagate drives out of service.

Historically, HGST (formerly Hitachi Global Storage Technologies, but now owned by Western Digital) hard drives have been by far the most reliable, but in 2015, Backblaze still went for Seagate. The company explains that "the HGST 4TB drives, while showing exceptionally low failure rates, are no longer available having been replaced with higher priced, higher performing models. The readily available and highly competitive price of the Seagate 4TB drives, along with their solid performance and respectable failure rates, have made them our drive of choice."

Backblaze now reports that the Seagate 4TB hard drives had a failure rate of just under 3 percent, which was only a little higher than the 4TB WD models (barchart below).

Read more: The most reliable hard drives in 2015, according to Backblaze | ZDNet