Something to keep in mind is that Backblaze has a business plan that is unique among large volume HDD users so finding another large volume HDD user that is comparable to Backblaze. Instead of using expensive, high quality enterprise grade HDDs like pretty much everyone else in the mass data storage business uses to avoid frequent HDD replacements, Backblaze uses inexpensive (and downright cheap), consumer grade HDDs, including ones cannibalized from external HDDs, the theory being it costs less to use cheaper HDDs and replace them more frequently instead of more expensive HDDs that don't need as frequent replacement. so far, that business plan seems to be working for them.
Even though Backblaze is using consumer drives in a way they were never intended to be used (running 24/7 instead no more than 8 hours a day), it's report on HDD reliability is still useful to consumers since it shows a very general comparison of how well one brand of HDD stacks up to another as far as HDD life is concerned. What the test doesn't show is that some brands of HDDs have changed ownership over the time of the test (HGST, for example), which may or may not have an effect on future HDD reliability, the cost of HDDs over time (an example is Seagates may fail more frequently than WDs but Seagates cost considerably less than WDs), length of warranty (WD is king, followed by HGST, then Seagate), the quality level of customer service when making a warranty claim (WD beats the holy, hairy heck out of Seagate here, and the tier of the HDDs used (Backblaze use the lowest priced HDDs it can lay its hands on so higher tier HDDs aren't being compared), etc.
Because of the factors I just mentioned, the comparisons have to be generalized, meaning the differences between HGST and WD are insignificant since they are so close to each other but, since Seagate is so far more dramatically different from the other two, it is worth noting. What means more to me is warranty length (suggest better reliability) and customer service levels. One can glean that information from customer reviews. One must read the reviews themselves, however, rather than just the number of stars, eggs, or whatever, to weed out the ones from people who are clueless, reporting a HDD is wonderful after a whole day of operation, complaining of DOAs that could be due to poor shipping, etc. I prefer WDs over Seagates based on my personal experience (however, personal experience vary from person to person), warranty length, and customer service levels on warranty claims (WD beats the snot out of Seagate, based mostly on customer reviews and partially on my own experience).
) and enterprise drives are designed for 24/7 operation.
