The backup specialist Backblaze regularly publishes quarterly and annual reports that provide information on the annual failure rates of the hard drives used. The now published annual report for 2020 includes the data from 162,299 hard drives that are currently in operation. The combined annual failure rate of all hard drive models halved from 1.89 percent in 2019 to 0.93 percent in 2020.
Hard drives with low failure rates
According to Backblaze, the lowest annual failure rate (Annualized Failure Rate, or AFR for short) among the hard drives can be seen in a 6 TB model with the designation ST6000DX000 from Seagate. Only 0.23 percent of the records failed on average in the previous year. The Seagate model is also the HDD with the highest average age among the hard drives that were included in the statistics.
Closely behind are the two 4-TByte models from the previous manufacturer HGST with the designations HMS5C4040ALE640 and HMS5C4040BLE640, each with 0.27 percent AFR. The 8-TByte model HUH728080ALE600 also did well with 0.29 percent AFR and the 12-TByte model HUH721212ALE600 with 0.31 percent AFR. Both also come from the manufacturer HGST, which Western Digital bought in 2011 and has since crushed the name.
Framework of the published data
For hard disk models that do not yet have a combined runtime of 250,000 days, conclusions from the annual failure rates are not appropriate, explains Backblaze in a blog post. Even if only a few copies of a model series are in use, the AFR value should be treated with caution. Because the operating mode differs greatly, boot hard drives are not included in the survey, only devices on which the customer’s data is stored. HDDs models that are in active use with fewer than 60 copies are also not taken into account. Although the publication is not a classic long-term test scenario, the values may be interesting for people who want to get a hard drive for their home NAS.
In the blog post Interested parties can find more information, including information on the methodology used and information on how to interpret the data. Backblaze poses in Download area of the website the raw data is also available.