This is a discouraging but welcome reminder to back up my stuff. I have a lot of important data on Seagate drives.
As you can see from the graph above, Hitachi drives are by far the most reliable. Even though most of Backblaze’s Hitachi drives are now older than two years, they only have an annual failure rate of around 1%. The “annual failure rate” is the chance of a drive dying within a 12-month period. After three years of being powered up 24/7, 96.9% of Hitachi drives are still running.
Western Digital is slightly worse, but still impressive: After three years of operation, 94.8% of Western Digital drives are still running. Backblaze lists the annual failure rate of the WD drives at around 3% (I don’t think the numbers quite add up, but I could be wrong).
Seagate drives are not very reliable at all. As you can see in the second graph below, Seagate drives are fine for the first year, but failures quickly start building up after 18 months. By the end of the third year, just 73.5% of Backblaze’s Seagate drives are still running. This equates to an annual failure rate of 8-9%.