Backblaze report: 8-terabyte HDDs lasting a long time - HGST Most Reliable

Online and cloud service provider Backblaze released a new listing of HDD failure rates for Q4 2017. At the end of 2016 they had 73,653 spinning hard drives. Of that number, there were 1,553 boot drives and 72,100 data drives. 

Data shows that 8TB models had fewer failures (1.65%) then smaller versions. Also failures overall compared to the last few years seem to have declined (1.94%). The 8TB HDDs mostly used are the Seagate ST8000DM002:
  

 
Backplaze has decided the phase out HDDs smaller then 3 TB, hence the lacking results. A HDD that has seen large failure rates however is the ST4000DX000 with 13.57%, it was a 3 years old series though.

Despite failure rates remained high for Seagate, there was one party with even higher failure rates, Western Digital with 3.88% of all HDDs. HGST remains the most reliable brand, but the irony is that they are owned by WD.

 
At the end of Q4 2016 Backblaze was monitoring 72,100 data drives. For our evaluation we remove from consideration those drives which were used for testing purposes and those drive models for which we did not have at least 45 drives. This leaves us with 71,939 production hard drives.

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In Q4 2016 we introduced a third 8 TB drive model, the Seagate ST8000NM0055. This is an enterprise class drive. One 60-drive Storage Pod was deployed mid-Q4 and the initial results look promising as there have been no failures to date. Given our past disdain for overpaying for enterprise drives, it will be interesting to see how these drives perform.

We added 3,540 Seagate 8 TB drives, model ST8000DM002, giving us 8,660 of these drives. That’s 69 petabytes of raw storage, before formatting and encoding, or about 22% of our current data storage capacity. The failure rate for the quarter of these 8 TB drives was a very respectable 1.65%. That’s lower than the Q4 failure rate of 1.94% for all of the hard drives in the table above.

During the next couple of calendar quarters we’ll monitor how the new enterprise 8 TB drives compare to the consumer 8 TB drives. We’re interested to know which models deliver the best value and we bet you are too. We’ll let you know what we find.

2016 Hard Drive Performance Statistics

Looking back over 2016, we added 15,646 hard drives, and migrated 110 Storage Pods (4,950 drives) from 1-, 1.5-, and 2 TB drives to 4-, 6- and 8 TB drives. Below are the hard drive failure stats for 2016. As with the quarterly results, we have removed any non-production drives and any models that had less than 45 drives.

n 2016, three drives models ended the year with zero failures, albeit with a small number of drives. Both the 4 TB Toshiba and the 8 TB HGST models went the entire year without a drive failure. The 8 TB Seagate (ST8000NM0055) drives, which were deployed in November 2016, also recorded no failures.

The total number of failed drives was 1,225 for the year. That’s 3.36 drive failures per day or about 5 drives per workday, a very manageable workload. Of course, that’s easy for me to say, since I am not the one swapping out drives.

The overall hard drive failure rate for 2016 was 1.95%. That’s down from 2.47% in 2015 and well below the 6.39% failure rate for 2014.

Big Drives Rule

We increased storage density by moving to higher-capacity drives. That helped us end 2016 with 3 TB drives being the smallest density drives in our data centers. During 2017, we will begin migrating from the 3.0 TB drives to larger-sized drives. Here’s the distribution of our hard drives in our data centers by size for 2016.