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I'm reviewing SMART attribute data for different disks and notice that some disks report the following attributes while other disks don't:

  • 241 0xF1 Total LBAs Written
  • 242 0xF2 Total LBAs Read

What determines whether this attribute is available for a given drive, and is there a way to tell this by looking at smartctl or hdparm output?

  • Are you using hardware RAID or software RAID? – ewwhite Feb 17 '13 at 22:50
  • Lets assume neither, good question. – AJ. Feb 17 '13 at 23:00
  • Gotta love a down vote without a comment. – AJ. Feb 18 '13 at 3:35
  • @AJ. it's true, the downvote should have included a comment. Don't know why it was downvoted, but my guess is that you didn't demonstrate any research. See my comment in Michael Hampton's answer below. The most obvious place on the internet (after Google)- Wikipedia- makes it pretty clear that drive manufacturers have a tremendous amount of leeway in what they provide via SMART, and how the define those things. Still, I appreciate finding this question on StackExchange and I have upvoted it just for future generations to find. – Mike S Sep 10 '15 at 12:42
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The hard drive manufacturer decides what SMART attributes they will expose to you. If they decide not to track or give you that information, you can't really get it.

As for how you determine what attributes are available, you look at the smartctl output, just as you already did.

  • Maybe there's no better answer, but "if it's there, it's there, else it's not" is an obvious tautology. What would be helpful here: 1) Is there a drive-level setting that one could key off of to know whether those metrics should be expected in the attribute table? 2) Can you provide a reference to any info you've read that says "drive manufacturer decides what SMART attributes they will expose to you"? – AJ. Feb 17 '13 at 22:37
  • This is a fine question, because it's not obvious that SMART data will vary amongst manufacturers. However, AJ should refer to the Wikipedia article on S.M.A.R.T, where it states quite clearly: "Each drive manufacturer defines a set of attributes", "Each attribute has a raw value, whose meaning is entirely up to the drive manufacturer", "From a legal perspective, the term "S.M.A.R.T." refers only to a signaling method...", "a disk manufacturer could ... produce a drive which includes a sensor for just one physical attribute, and then legally advertise the product as "S.M.A.R.T. compatible"." – Mike S Sep 10 '15 at 12:39

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