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Re: Need second opinion, is my HD failing?

Paulo Cavalcanti wrote:
But in Richard's case, 955 seems odd to me:

5 Reallocated_Sector_Ct   0x0033   100   100   036    Pre-fail    Always
  -       955

Probably, you are right, and the value is OK. But I have never seen a
counting like
this before. I had a defective disk once, which increased 20 or 30 bad
sectors a day.
Therefore, such a high score would not be a surprise for me (Seagate
replaced the disk for me,
even it being more than 2 years old).

It is quite a high number and many of my drives do have raw values much closer to zero, although I have at least a few with raw values in the 100s that still have 100 as the normalised value and are working fine.

The problem with trying to interpret the raw values is that they are completely under the control of the vendor. The only thing S.M.A.R.T. specifies is the size of the field. Some vendors have previously taken a single field and used it to encode multiple values (e.g. breaking it up into several sub-fields). For example, some IBM drives encode three distinct temperature measurements in the raw value for the Temperature_Celsius attribute.

Because of this, unless you know the scheme being used for a given vendor/drive model it's impossible to make any accurate assumption from the raw value alone - you just have to trust the firmware to decrement the normalised value appropriately as the drive begins to deteriorate.


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