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Data Center Study Reveals Top 5 SMART Stats That Correlate To Drive Failures

Posted by samzenpus on from the about-to-go dept.

Lucas123 writes Backblaze, which has taken to publishing data on hard drive failure rates in its data center, has just released data from a new study of nearly 40,000 spindles revealing what it said are the top 5 SMART (Self-Monitoring, Analysis and Reporting Technology) values that correlate most closely with impending drive failures. The study also revealed that many SMART values that one would innately consider related to drive failures, actually don't relate it it at all. Gleb Budman, CEO of Backblaze, said the problem is that the industry has created vendor specific values, so that a stat related to one drive and manufacturer may not relate to another. "SMART 1 might seem correlated to drive failure rates, but actually it's more of an indication that different drive vendors are using it themselves for different things," Budman said. "Seagate wants to track something, but only they know what that is. Western Digital uses SMART for something else — neither will tell you what it is."

7 of 142 comments (clear)

  1. Skip the blogspam, here's the real link by Anonymous Coward · · Score: 5, Informative

    https://www.backblaze.com/blog/hard-drive-smart-stats/

    Goes into a lot more detail too.

  2. The measurements in question: by Immerman · · Score: 4, Informative

    for those who are only passingly curious and don't want to read the article.
            SMART 5 - Reallocated_Sector_Count.
            SMART 187 - Reported_Uncorrectable_Errors.
            SMART 188 - Command_Timeout.
            SMART 197 - Current_Pending_Sector_Count.
            SMART 198 - Offline_Uncorrectable

    --
    --- Most topics have many sides worth arguing, allow me to take one opposite you.
    1. Re:The measurements in question: by omnichad · · Score: 4, Informative

      And I can confirm. Reallocated Sector Count rarely goes above zero when the drive is fine. It's possible to have a few sectors go bad and get reallocated, but it's usually part of a bigger problem when it happens (this number is reset to zero at the factory, after all initially bad sectors have been remapped). If the Current Pending Sector Count is non-zero, it's likely over.

      I always clone a drive immediately with ddrescue when it gets to this point, while the drive is still working.

    2. Re:The measurements in question: by koinu · · Score: 3, Informative

      Reallocated_Sector_Count sectors that the drive successfully replaced Reported_Uncorrectable_Errors errors that could not be recovered by ECC Command_Timeout controller hanging and had to be resetted Current_Pending_Sector_Count sectors to be replace by the next write access Offline_Uncorrectable sectors that the drive tried to repair, but failed (try offline test, maybe it is not dead yet)

    3. Re:The measurements in question: by omnichad · · Score: 3, Informative

      Also, generally you don't need to panic over this attribute. You should panic when it increases steadily.

      True, I've had a few drives hold steady at 1 sector reallocated. But if Current Pending Sector count remains non-zero for very long, it's a headache at the very least and probably a failure. Generally, it seems like as soon as you crest zero, it's over. I've had the next symptom be a totally unresponsive drive. But doing the backup when you hit 1 (admittedly overly cautious) will force the drive to read off all the sectors and you'll at least get your backup while you verify the rest of the drive still reads OK.

  3. Re: Seagate OEM? by corychristison · · Score: 3, Informative

    I buy whatever is cheapest.

    I know it's a toss up no matter what or when you buy hard drives, so the only thing I have left to guage is price, capacity, and speed (RPM) depending on the intended use.

    About a year ago I took a gamble on an SSD for my primary workstation. I bought an ADATA SX900 64GB drive. I had never heard of the brand before. It was ~$120 at the time, and the cheapest for that capacity. I've been looking at getting a 128GB (or so) SSD for my laptop. Prices right now look like I will be getting another ADATA... but I am holding out for Black Friday/Cyber Monday deals to decide.

    Oddly enough, over the past 10 years, I've never had a hard drive die in any of my computers while in use. I have a stack of 4 or 5 drives, ranging in capacity from 100GB to 500GB, 3 different different brands, that I'm not using right now. A while back, I plugged one in just to see if it still worked and it didn't. I recently found out it was the hotswap bay that quit working, so as far as I know it still works.

    Conversely, I have some servers in a datacenter. Had a drive fail on reboot after a kernel upgrade the other night. Sent a ticket to the DC and they plugged a new one in. Good to go again. In case you're wondering, it has 4x600GB SAS drives in RAID-10.

    TL;DR: Buy whatever is cheapest, the odds are always the same.

  4. Re:Put the SMART stats to the test by brianwski · · Score: 3, Informative

    Disclaimer: I work at Backblaze. Essentially this is what we did. We don't care at all if one drive dies, so we left it in an environment where we can read and write them all day (the storage pods with live customer data) and when they failed we calmly replaced them with zero customer data loss and produced this blog post. :-)