The company compared active hard drives used in its operations - from Seagate, Western Digital, Toshiba, and HGST - for the report.
Reliability was measured as an annualised failure rate, calculated using the number of drive failures relative to the number of active drive days.
Backblaze then recorded the failure rates of its hard drives from 1 January to 31 December 2018, along with the annualised failure rate.
The backup provider had 106,919 spinning drives as of 31 December 2019, and added a number of models to its archive throughout the year.
"In 2018 the big trend was hard drive migration: replacing lower-density 2TB, 3TB, and 4TB drives, with 8, 10, 12, and in Q4, 14 terabyte drives," Backblaze said.
Over the course of the year, Backblaze increased its total storage from around 500 petabytes to over 750 petabytes.
The most reliable hard drives for 2018, as well as their lifetime failure rates from 20 April 2013 to 31 December 2018, are listed below.
2018 Failure Rates
Lifetime Failure Rates – 2013 to 2018