SMART errors - are they for real? or, BIOS weirdness?

[Robin Laing]

Tim wrote:
> Thufir:
>>> I'm getting SMART errors, but I'm not sure how much credence to give 
>>> them.  It seems to be the same two e-mails over and over.
>>>
>>> The following warning/error was logged by the smartd daemon:
>>>
>>> Device: /dev/hdb, 2 Currently unreadable (pending) sectors
> 
> Bruno Wolff III:
>> It might be that the drive firmware has a bug where as the pending sector
>> count doesn't always get cleared when the sectors are reallocated. I have
>> a Maxtor drive that has that problem.
>>
>> It might also be that you have never written of the bad sectors so the drive
>> can't reallocate them. If they really can't be read a long scan should be
>> showing up a bad sector that you can then find the file it is contained in
>> (so you know what you are losing) and then rewrite that sector (actually
>> you want to rewrite the whole 8 sector block to keep the OS from trying
>> to read the surrounding sectors). If the sector is permanently bad the drive
>> should reallocate it. Sometimes just an isolated write was bad and the sector
>> doesn't need to be remapped.
> 
> I had a system using LVM fail to boot, and when assessed using another
> drive (that would boot), got error reports like the above.  Wherever the
> errors were, it was some place that LVM really did not like.  I used dd
> to overwrite the entire drive, to try and force a write to wherever it
> was, and force the drive to try and fix what it could, and the errors
> got cleared up.
> 
> Nothing else I had tried cleared up the errors.  The system got
> reinstalled, without LVM, just to see if the drive would keep on
> working, and it has.  It's many months later, and there's no error
> reports, including while making deliberate checks.
> 

I have had the same issue with a Western Digital as well.  A WD5200 
started giving these errors in FC6.  Less than a year old.

I have since replaced the drive and put the WD in a USB carrier.  Two 
complete wipes and reformats and tests and no errors found.

I wonder if it is an issue with SMART and the drives?

-- 
Due to the move to M$ Exchange Server,
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Robin Laing