Bad sectors/health question

[raster65]

I have a Seagate 1 TB drive (ST31000528AS) that, I believe, has ~2 billion sectors.

If that's the case, why does an 11 bad sectors count reduce health dramatically to 83%, as reported by HDS 4.30 ?
Mathematically, that just doesn't make sense to me. You'd think that it would be a very small fraction of 1%.

The drive started it's first bad sector after only 2 weeks and now has 211 days power on time. Is this drive going to fail prematurely? Thanks

[hdsentinel]

Thanks for your message and excuse me for the possible confusion.
I completely agree that you may feel that 11 (or even 12, 15, 100 or 1000) sectors is a very low number compared to the total sectors on the hard disk.
Even if this may sounds surprising, the problem is not really the 11 bad sectors.
As you may know, these bad sectors are no longer used: instead of them, the hard disk uses a special spare area (the sectors are "reallocated"). It means all reads/writes target these spare sectors for the entire lifetime of the hard disk (regardless of any software and operation), which means that the mentioned 11 bad sectors will never cause problems.

(for more information, about these "bad sectors", please click on the "?" next to the text description (the text area describing the issues) and check
http://www.hdsentinel.com/faq.php#health and
http://www.hdsentinel.com/faq.php#tests ).

Technically relatively low number of such bad sectors (even one) can cause data loss, depending on the situation, the area (sector position) affected and so.

The more important questions are:

- what may caused these bad sectors?
- are there any further problem(s) which may be not yet detected? (for example possible bad sectors on less frequently used areas of the hard disk)
- do we have all bad sectors reallocated?
- how it is possible to investigate them, force the drive to replace them with the spare area (if required) to prevent problems with them?

If the number of such bad sectors relatively low, they may not indicate big problem, especially if the status of the hard disk is stable, there are no further problems detected after detailed investigation (described at http://www.hdsentinel.com/faq.php#tests )
But if the number of bad sectors start to increase (to some 100's or even 1000's) this may indicate bigger problem with the disk disk surface and/or the head which can relatively quickly lead to complete data loss - even if the 1000 sector still seems nothing compared to the total number of sectors of the hard disk.

Personally in this or similar situations, I'd recommend to check http://www.hdsentinel.com/faq_repair_ha ... _drive.php
and http://www.hdsentinel.com/faq.php#tests
pages. These describe how Hard Disk Sentinel can be used to diagose the hard disk drive, reveal and fix possible problems and if the tests confirm that the status is stable, how it is possible to acknowledge the reported problems, clear the error counters (and restore the health of the hard disk to higher level, maybe even to 100%). This way Hard Disk Sentinel will only report any future problems with the hard disk.

If you prefer, you can use Report -> Send test report to developer option any time (now and/or after the tests, to check the status of the hard disk, verify if the status would change somehow).

If you are interested in further details, I'd recommend to read Support -> Knowledge base -> Hard disk cases page.
"Hard disk case: bad sectors" ( http://www.hdsentinel.com/hard_disk_cas ... ectors.php ) page may give further details.

[raster65]

Thank you for your very detailed and informative response. At this time there are no other problems with the drive and I will check the links you provided.