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BK3

join:2001-04-10
Geneva, IL
Reviews:
·AT&T Yahoo

HDD - What am I missing?

Click for full size
No bad sectors found
Click for full size
3 reallocated sectors
When using HDD tune, and I do an error scan, the program finds no bad sectors on the drive, however, the SMART scan reports 3 reallocated sectors. I was under the impression that reallocated sectors implied that some bad sectors were detected. Am I wrong?
--
Learn from the past and look to the future.


psafux
Premium,VIP
join:2005-11-10
kudos:2
If the sector was reallocated the bad sector was written off as being usable by the drive. Nothing else will (should) attempt to enter the written off sector. The error scan doesn't see the bad sectors because they aren't active. The SMART scan is a tally, it doesn't (shouldn't) reset. There is a finite amount of reallocation space and (in my opinion) a drive with reallocated sectors is more likely to fail than one that doesn't.


koitsu
Premium,MVM
join:2002-07-16
Mountain View, CA
kudos:23
reply to BK3
The sectors were not reallocated; the LBAs were reallocated.

Speaking with regards to your model of drive:

SMART attribute 0x05 shows clearly that you have 3 LBAs which point to alternate/spare sectors on the drive (i.e. instead of LBA 12345 pointing to sector 12345, LBA 12345 now points to sector 83982925782).

At some point during the drive's lifetime, it encountered 3 anomalies either during reading or writing. If during reading, an I/O error would be returned, SMART attribute 0xC5 would be incremented, and the LBA would no longer be readable until a write was issued to it. I refer to this behaviour as an LBA that is "suspect". MHDDs only do analysis of "suspect" LBAs when a write is issued to the LBA in question.

If during writing, the drive did the necessary analysis and determined that the LBAs in question pointed to sectors which could no longer be used (and that includes ECC being unusable), thus remapped those LBAs to spares. It did all of this during one event (tracked by SMART attribute 0xC4), rather than across multiple events (meaning, the write to the disk was probably in an amount that spanned multiple LBAs). When a remapping occurs, attribute 0xC5 is decremented.

SMART attribute 0xC6 is zero, which indicates all remappings were successful.

Your drive also tends to park its heads a lot (over 123 thousand parks with only a 9200 power-on hour count). If this is a 2.5" drive (e.g. laptop drive), this is fine/normal/acceptable.

HD Tune's author makes the assumption that a non-zero value in attribute 0x05 is worthy of showing the row in yellow -- that's the choice of the author, while SMART itself shows the attribute has not tripped (i.e. drive is still healthy when compared to vendor-defined thresholds).

Finally: going forward, you should not use HD Tune 2.55; this software is quite old and is very buggy. You should use HD Tune Pro, even if only the trial version.
--
Making life hard for others since 1977.
I speak for myself and not my employer/affiliates of my employer.


BK3

join:2001-04-10
Geneva, IL
Reviews:
·AT&T Yahoo
Thank you for your reply. It was quite complete and tells me all I wanted to know. I just have 1 question:

Is this drive usable / reliable enough for use, or should I swap it out ASAP? It seems to be working OK.
--
Learn from the past and look to the future.


koitsu
Premium,MVM
join:2002-07-16
Mountain View, CA
kudos:23
The drive at this time has no other indications of problems/issues, so I would say as long as it's working fine for you and you haven't encountered any issues (I/O errors or 100% repeatable anomalies with any software), then stick with it. I will admit that 3 remapped LBAs for 9000 hours could be considered (by some) to be a bit high, but for a 2.5" form factor drive, I would say it's fine. If that number starts to grow/get worse, or you start to see attributes 0x01, 0xC6, or 0xC8 increment, then I'd recommend replacing it.
--
Making life hard for others since 1977.
I speak for myself and not my employer/affiliates of my employer.