A little over a year into the life of my first ever laptop—a Powerbook G4, if you’re curious—the hard drive straight up died on me, seemingly for no reason. Enough stuff was backed up elsewhere that it wasn’t exactly a tragedy; the worst part was the fact that Apple made me pay to replace it. But the replacement hard drive outlasted that laptop, even surviving when a kicked cup of water burned out the logic board; I just took the hard drive out of the burnt-out body and popped it into another Powerbook body. It’s probably still working today, ready to be plugged in and play Tha Carter III as soon as you uncover it from my parent’s basement.
So if you ask me how long a hard disk lasts, I’d probably say either forever or exactly one month longer than your warranty—and until Backblaze released a study today, guesses like that were all we had. Now we know—not with 100 percent certainty, but more objectively than before—how long you can reasonably count on a hard drive.
Turns out, my experience with the Powerbook was pretty standard. According to Backblaze, about one in 20 hard drives fails in the first 18 months. The failure rate drops to just 1.4 percent after this initial break-in period, before jumping up to 11.8 percent annually after 3 years.
Beyond that time period, though, Backblaze doesn’t have much data—they’ve only been around and collecting this data for four years. Still the fact that 74 percent of hard drives that they buy last longer than 4 years strikes me as pretty surprising. It also makes perfect sense that, as Backblaze points out, most available hard drive warranties are either 12 or 36 months.
As an online backup service, Backblaze keeps 25,000 disk drives spinning along, which add up to 75 petabytes of storage. Over the life of their company they recorded when hard disks needed to be replaced, producing a formidable sample size, even if there are caveats when comparing a hard drive in a home computer with one in a rack in a data center running 24 hours a day.
But the report does make sense of my experience, at least: Factory defects filter out that first 5 percent in the first 18 months, then the hard drives hit their groove. Random breakdowns occur, but not frequently. Then after the 3-year mark, the components start to wear out.
As Backblaze doesn’t have any hard drives that are older than its company it can only estimate that, based on the data already collected, the median hard drive life is about six years.
Naturally they’ll be testing this as time goes on, and, just as naturally, encouraging people to use their backup service in the meantime. The study is another solemn reminder that, as much as we like to think of the internet as a leap to immortality, data is ever-fleeting.
As I think back on my now long-defunct Powerbook, I guess would be reasonable to expect a hard drive to last longer than my first one. The fact that the second hard drive probably still works is kind of unnecessary, given that the rest of it—and indeed contemporary electronics culture—used planned obsolescence as a guiding principle.