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Bad sector on harddrive - could it cause failure?

Last response: in Storage
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March 26, 2011 8:25:06 AM


I just discovered that one of my drives reports a bad sector. The drive is quite new, a Samsung F3 1 TB, and has been used for less than a year. I have not seen bad sectors reported on drives for ten years or something, so this does not feel good.

Do you think that this is a sign of the drive being bad and should be replaced?


C:\>chkdsk T:
The type of the file system is NTFS.
Volume label is 0-3-ISO-TRCS.

WARNING! F parameter not specified.
Running CHKDSK in read-only mode.

CHKDSK is verifying files (stage 1 of 3)...
50688 file records processed.
File verification completed.
153 large file records processed.
0 bad file records processed.
0 EA records processed.
0 reparse records processed.
CHKDSK is verifying indexes (stage 2 of 3)...
52058 index entries processed.
Index verification completed.
0 unindexed files scanned.
0 unindexed files recovered.
CHKDSK is verifying security descriptors (stage 3 of 3)...
50688 file SDs/SIDs processed.
Security descriptor verification completed.
685 data files processed.
Windows has checked the file system and found no problems.

700279807 KB total disk space.
72184324 KB in 45357 files.
17508 KB in 687 indexes.
4 KB in bad sectors.
138023 KB in use by the system.
65536 KB occupied by the log file.
627939948 KB available on disk.

4096 bytes in each allocation unit.
175069951 total allocation units on disk.
156984987 allocation units available on disk.
a b G Storage
March 26, 2011 12:54:01 PM

Yes in some cases bad sectors can cause a drive to become inaccessible. Backup your data ASAP and replace the drive. Once bad sectors start to develop more are likely to follow. Also check the warranty status you may be able to get it replaced for free.
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a c 415 G Storage
March 26, 2011 6:58:27 PM

IMHO a single bad sector is not a good reason to discard a disk. Take a deeper look at the state of your drive use a utility such as "DiskCheckup" that can report the drive's SMART error counters.

The worst kind of error is the "Pending Sector" count - it indicates a sector which contains data that can't be read. The "Reallocated Sector" count indicates sectors which have failed but whose contents were recovered and placed into alternate locations.

If the error counts are stable as you use the drive and if they're not excessive then your drive is probably safe to use. But if the error counts are increasing day by day then you should feel very nervous about it.

Hopefully you're making regular backups anyway. One of the benefits that a lot of people overlook in making regular backups is that doing so causes the drive to read every used sector on the drive - this means that the SMART error counts are a good indication of the state of ALL your data, not just the data you happen to be using at any time.

Of course this isn't true if your backup package uses a "full backup the first time and then nothing but incrementals forever after" strategy - a strategy I personally dislike and avoid.
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March 26, 2011 7:07:56 PM

sminlal said:
IMHO a single bad sector is not a good reason to discard a disk. Take a deeper look at the state of your drive use a utility such as "DiskCheckup" that can report the drive's SMART error counters.


Thanks for your reply. I shall download the tool above and see what it reports.

As for the now found damaged sector, will NFTS take care of it, so if the files are moved inside the drive or if it is defragmented - then the sector should have been "taken out" by NTFS?
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March 26, 2011 7:13:06 PM

NTFS and the drive firmware should recognize bad sectors and reallocate new sectors to take the place of the bad ones. In fact, IIRC, SSDs and HDDs actually reserve unused sectors as spare sectors that are then used when in use sectors go bad.
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March 26, 2011 8:16:47 PM


Thanks for your replies so far. I have now been testing the DiskCheckup tool and I have some results that does not look to good.

In the computer I have two identical Samsung F3 1TB and I have compared the results on both. The picture below is on the drive with the reported bad sector and for almost all values the two discs were very similar, and where there is a change I have noticed it.



So, what do you make of these numbers? It is quite hard to see if they are too high. The tool reports "OK" for all tests, but it does not feel good with quite large amounts of errors being reported.
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a c 415 G Storage
March 26, 2011 9:24:45 PM

You can get a better idea of what the numbers mean here. In particular, note that ID 1 (Raw Read Error Rate) may not represent a numeric value but rather a bit-encoded field, so "722" may not represent a lot of errors.

G-Sense Error rate shows the number of times there was a read error due to physical shock to the drive. It's perfectly normal for the drive to mis-read data if it's being subjected to shock or vibration - the drive will simply re-try until it's able to read the data successfully.

The thing that stands out for me is that there's only 1 pending sector (which is doubtless the one that CHKDSK detected) and no reallocated sectors (Reallocation Event Count = 0). That basically means there's only 1 bad sector on the disk, which I wouldn't consider to be a big problem. I'd keep an eye on those two numbers - if they start going up then you've got cause for concern.

I'd also think about why the drive is reporting write errors due to shocks or vibrations - anything you can do to reduce or eliminate that will be good for your drive. It's quite possible that the reason your bad sector is bad is because it wasn't written correctly due to a shock at the wrong time.
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April 2, 2011 8:55:32 AM

sminlal said:
In particular, note that ID 1 (Raw Read Error Rate) may not represent a numeric value but rather a bit-encoded field, so "722" may not represent a lot of errors.


Thanks for your reply. I have been following the values for a week now and for example the ID1 field above has increased up to around 800, but as you say, it is not really known what the value represents.

sminlal said:

The thing that stands out for me is that there's only 1 pending sector (which is doubtless the one that CHKDSK detected) and no reallocated sectors (Reallocation Event Count = 0). That basically means there's only 1 bad sector on the disk, which I wouldn't consider to be a big problem.


This value is still 1, which should mean that there is a single damaged sector on the drive. If NTFS is aware of that and can avoid to use it there should be no problem. It is just somehting that looks a bad these days, I have not seen damaged sectors on drives for many years.


sminlal said:
I'd also think about why the drive is reporting write errors due to shocks or vibrations - anything you can do to reduce or eliminate that will be good for your drive. It's quite possible that the reason your bad sector is bad is because it wasn't written correctly due to a shock at the wrong time.


The computer is a stationary PC which stands very still, so I do not think shocks or vibrations have caused this. However, directly after I built the computer there was some problems with power resets. The computer suddenly just reset perhaps five times. That problem is solved now, but do you think that could have caused "shock like" work for the disk?

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April 2, 2011 11:50:00 AM

Bad sectors can be caused due to hardware unstability during system running, you can run some disk defrag to fix bad sectors.
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April 2, 2011 12:37:32 PM

techeasy said:
you can run some disk defrag to fix bad sectors.


Thanks for your reply. What do you mean with fixing the bad sectors? And should a defrag tool be able to do something about such damaged sectors? From what I think the filesystem should spot the bad hardware sectors and in some way mark them as unavailable.
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a c 415 G Storage
April 2, 2011 5:47:02 PM

ricno said:
This value is still 1, which should mean that there is a single damaged sector on the drive. If NTFS is aware of that and can avoid to use it there should be no problem.
Since CHKDSK is showing 4K in bad sectors, it's probably safe to say that your pending sector has been remapped at the file system level and won't be used.

ricno said:
The computer is a stationary PC which stands very still, so I do not think shocks or vibrations have caused this. However, directly after I built the computer there was some problems with power resets. The computer suddenly just reset perhaps five times. That problem is solved now, but do you think that could have caused "shock like" work for the disk?
It doesn't strike me as likely, but I'm really not familiar enough with your drive to say.
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April 3, 2011 9:18:30 AM


I did a check with a new tool HDDscan (http://hddscan.com) and it reported the SMART values somewhat different in raw hex. However, it only reacted at the pending sector.



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April 10, 2011 5:45:15 AM

Best answer selected by ricno.
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