Solid state has made listening out for a hard drive's "click of death" an impossible task, but magnetic disks are still in heavy use, especially in server applications and knowing exactly when a drive is going to fail can't be left up to the sharpness of one's hearing. That's what SMART, or Self-Monitoring, Analysis, and Reporting Technology, is designed for, but getting any actionable information from a drive's SMART data is difficult at best. Through trial and error, one company has figured out which SMART stats you should be paying attention to.
As Computerworld's Lucas Mearian reports, Backblaze, an online backup provider, has been keeping an eye on SMART data from its servers and identifying which of the many values provide a reliable indication of impending failure. This isn't a straightforward task as the data is not consistent across hard drive models and manufacturers.
40,000 drives later, and the results are in:
SMART 5 - Reallocated_Sector_Count. SMART 187 - Reported_Uncorrectable_Errors. SMART 188 - Command_Timeout. SMART 197 - Current_Pending_Sector_Count. SMART 198 - Offline_Uncorrectable
In Backblaze's experience, the above five metrics were the most reliable and consistent when it came to predicting when a drive would give up the ghost. All you have to do to see the numbers for your own hardware is to grab a tool such as CrystalDiskInfo (it's free, just watch out for the browser bar in the installer) and poll your drives. Hopefully they're all in decent nick.
The 5 SMART stats that actually predict hard drive failure [Computerworld]