Reallocated sector count on Hitachi 1TB HDD

[Dystopianfreak]

Alright, I'm trying to help a friend who has a Hitachi HDS721010CLA332 1TB HDD.
He recently defragmented it with Defraggler but it never completed and now Defraggler and Windows report that there is a problem with his HDD and are pointing to the Reallocated Sector Count, which has these attributes:
Real Value: 2007
Current: 1
Worst: 1
Threshold: 5

I had him run a full scan CHKDSK which took a whole day and reported nothing and I am having him run a full defrag on the HDD. I am wondering if the hard drive is ruined or if this S.M.A.R.T. data is even a cause for alarm (I am not very familiar with S.M.A.R.T. data). The raw value for his Reallocated Sector Count is 0x0000000007D7.

[Vulcan]

I am wondering if the hard drive is ruined or if this S.M.A.R.T. data is even a cause for alarm (I am not very familiar with S.M.A.R.T. data). The raw value for his Reallocated Sector Count is 0x0000000007D7.

Yes the disk is dying (and could fail catastrophically soon). Before deciding what to do, you need to consider whether your friend needs the data off the disk, and if so, whether it has enough value to pay a DR company to attempt the recovery, or whether you'll decide to take the risks of making things worse by trying some DIY recovery (although, with respect, I'm not sure you've got the necessary experience to try that).

Good luck with whatever you decide.

P.S. The defrag was absolutely the wrong thing to recommend to your friend but I don't work with Windows sys admin and so I don't know if that can be stopped without causing further problems.

[Dystopianfreak]

The hard drive still works, and so data recovery would be easy, especially considering he has multiple setups. My question is simply how did this happen? It seems like formatting the disc would skip the bad sectors. Am I wrong in assuming this? Any more info on what exactly is wrong with the HDD in question would be appreciated.

[Vulcan]

The hard drive still works, and so data recovery would be easy

You haven't supplied all of the SMART data, so I cannot confirm or deny your assertion. It is possible that not all sectors are readable, and so not all data could be recovered; or the disk could fail catastrophically in 7minutes from now (or whatever ), which would again not fit with your assertion. etc. etc.

My question is simply how did this happen?

My crystal ball needs cleaning. Seriously, that's not a simple question. You would need to consider all the history of the drive, to see whether you had done anything mechanical, electrical or chemical to cause premature failure. Or there could have been an underlying microscopic manufacturing defect, or damage caused in transit at any time before you got the disk, or ...

It seems like formatting the disc would skip the bad sectors. Am I wrong in assuming this?

Yes, you're wrong in assuming it's that simple, especially for a disk which is as sick as yours. I don't have time to give a tutorial on disk drive behaviour, internal sector reallocations and the difference between that and what the OS sees when doing a format etc., but the situation is more complex than your question implies. Perhaps another reader can point you to a beginner's guide to disk formatting and sector reallocations.

Any more info on what exactly is wrong with the HDD in question would be appreciated.

That's impossible to diagnose exactly, especially when remote from the disk. If you're really interested, then you can pay a DR company to try to find out - but it's not always possible outside of the manufacturer's FA department, to find out exactly what is wrong (e.g. DR companies are not usually equipped to remove the encapsulation of ICs, to look for ESD damage). You have to accept (and expect) that a disk can fail at any time, which is why backups are essential.

All I can say from the (limited) info you've given, is that the disk is having problems reading some of the media (these problems might, or might not, be limited to reading from specific head(s)) and as a result it is using its limited number of spare sectors, instead of those hard-to-read areas of the media. The SMART data suggests that the disk might have used all (or nearly all) of its spare sectors already.

[BlackST]

Backup and replace or find someone who can professionally refurbish the drive. Simple.