HDD SMART data tracking to detect failing HDDs

Posted on Thursday, Nov 13 2014 @ 18:27 CET by Thomas De Maesschalck
Online storage firm Backblaze released a new report in which they investigated hard drive SMART metrics to discover which data can be used to predict HDD failures. The company says SMART stats are inconsistent from hard drive to hard drive but found that there are five SMART metrics that indicate impending disk drive failure. You can check it out over here.
A drive is considered to have stopped working when the drive appears physically dead (e.g. won’t power up), doesn’t respond to console commands or the RAID system tells us that the drive can’t be read or written.

To determine if a drive is going to fail soon we use SMART statistics as evidence to remove a drive before it fails catastrophically or impedes the operation of the Storage Pod volume.

From experience, we have found the following 5 SMART metrics indicate impending disk drive failure:

  • SMART 5 – Reallocated_Sector_Count.
  • SMART 187 – Reported_Uncorrectable_Errors.
  • SMART 188 – Command_Timeout.
  • SMART 197 – Current_Pending_Sector_Count.
  • SMART 198 – Offline_Uncorrectable.

    We chose these 5 stats based on our experience and input from others in the industry because they are consistent across manufacturers and they are good predictors of failure.
  • Factors like drive temperature were found to have no impact on the disk's failure rate.

    Backblaze SMART HDD investigation

    About the Author

    Thomas De Maesschalck

    Thomas has been messing with computer since early childhood and firmly believes the Internet is the best thing since sliced bread. Enjoys playing with new tech, is fascinated by science, and passionate about financial markets. When not behind a computer, he can be found with running shoes on or lifting heavy weights in the weight room.

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