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 Post subject: Best way to mark Bad Blocks on 1TB NTFS Disk?
PostPosted: January 27th, 2022, 14:08 
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Joined: November 13th, 2018, 6:16
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Location: United Kingdom
Apologies if this is already covered, please post a link if so.

I have a 1TB Samsung SATA hard drive on USB that I use for non critical copies & general work with read errors on a part of the disk and want to mark that area of the disk as 'bad blocks' , or whatever the correct terminology is, so that data does not get written to that area in future.
I had the idea of mounting the drive in a laptop and then booting from a USB stick and running something to scan & mark the bad areas on the disk. I'd prefer to keep the data on the disk intact, but can make backups & restore if needed to get a good result.
I would normally throw away a disk with errors, but as it's 1TB, even 90% is very useful.

Any ideas on what tools I can use? I can use Windows or Linux, not particularly fussed.

Thanks


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 Post subject: Re: Best way to mark Bad Blocks on 1TB NTFS Disk?
PostPosted: January 28th, 2022, 18:23 
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Just run the disc through a scanning program and select surface scan. It will take a few hours, but it will mark every bad sector and the computer will not write to it unless you format the drive again.


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 Post subject: Re: Best way to mark Bad Blocks on 1TB NTFS Disk?
PostPosted: January 29th, 2022, 11:00 
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ShaneWard wrote:
Just run the disc through a scanning program and select surface scan. It will take a few hours, but it will mark every bad sector and the computer will not write to it unless you format the drive again.


Once a sector is reallocated, it will remain that way, no file system format can change that.

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 Post subject: Re: Best way to mark Bad Blocks on 1TB NTFS Disk?
PostPosted: January 29th, 2022, 13:24 
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Joined: September 8th, 2009, 18:21
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Arch Stanton wrote:
ShaneWard wrote:
Just run the disc through a scanning program and select surface scan. It will take a few hours, but it will mark every bad sector and the computer will not write to it unless you format the drive again.


Once a sector is reallocated, it will remain that way, no file system format can change that.

If the "scanning program" is CHKDSK, then bad sectors would be marked by the file system. For example, NTFS would add these bads to the $BADCLUS metafile, and the OS would then avoid them. At least that's how I think it works.

SMART would probably identify these sectors as "pending reallocation". A subsequent format may cause the drive to reallocate these sectors or return them to service if they retest OK.

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 Post subject: Re: Best way to mark Bad Blocks on 1TB NTFS Disk?
PostPosted: January 29th, 2022, 13:30 
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fzabkar wrote:
If the "scanning program" is CHKDSK, then bad sectors would be marked by the file system. For example, NTFS would add these bads to the $BADCLUS metafile, and the OS would then avoid them. At least that's how I think it works.

SMART would probably identify these sectors as "pending reallocation". A subsequent format may cause the drive to reallocate these sectors or return them to service if they retest OK.


That's my understanding too from reading around the subject, I think FSCK will do something similar for EXT formatted drives. I was hoping to find a tool that would work below the OS format to mark the badspots at the controller level. I've been trying the Victoria disk tool today, but am not exactly sure what that's doing when it re-allocates sectors.


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 Post subject: Re: Best way to mark Bad Blocks on 1TB NTFS Disk?
PostPosted: February 1st, 2022, 11:52 
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Joined: December 13th, 2020, 18:47
Posts: 53
Location: recoverland
cancunia wrote:
Apologies if this is already covered, please post a link if so.

I have a 1TB Samsung SATA hard drive on USB that I use for non critical copies & general work with read errors on a part of the disk and want to mark that area of the disk as 'bad blocks' , or whatever the correct terminology is, so that data does not get written to that area in future.
I had the idea of mounting the drive in a laptop and then booting from a USB stick and running something to scan & mark the bad areas on the disk. I'd prefer to keep the data on the disk intact, but can make backups & restore if needed to get a good result.
I would normally throw away a disk with errors, but as it's 1TB, even 90% is very useful.

Any ideas on what tools I can use? I can use Windows or Linux, not particularly fussed.

Thanks


Your strategy is useless as it won't protect you against data loss.

When writing to a drive with defective sectors, defective sectors will be remapped as long as there are spares available.
So there is no use for your procedure when writing.

So you are only left with reading your drive. You can check your existing files on your broken drive if they are readible. Once reading a drive fails your operating system will probably update it's list of bad blocks. But the data is gone anyway. And when deleting the file and upon reallocation of the freed sectors/blocks/clusters the remapping will hide the defective sector anyway once the next write transaction occurs.

What will happen when faced with pending and/or reallocated sectors is that they use to grow. You will notice that once you are unable to read files that were able to read before.

As you are probably not doing backups as well, the present community of data recovery specialists hear will gladly try to recover your lost information for a hefty multiple of the price of a new and healthy drive.

Personally I don't understand why people are so keen on playing roulette with their drive.
Are those people extremely poor and cannot afford buying a new drive? But how come they own a computer?

If you want to play roulette, regularly monitor your SMART parameters.


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 Post subject: Re: Best way to mark Bad Blocks on 1TB NTFS Disk?
PostPosted: February 1st, 2022, 11:58 
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Joined: May 13th, 2019, 7:50
Posts: 907
Location: Nederland
fzabkar wrote:
Arch Stanton wrote:
ShaneWard wrote:
Just run the disc through a scanning program and select surface scan. It will take a few hours, but it will mark every bad sector and the computer will not write to it unless you format the drive again.


Once a sector is reallocated, it will remain that way, no file system format can change that.

If the "scanning program" is CHKDSK, then bad sectors would be marked by the file system. For example, NTFS would add these bads to the $BADCLUS metafile, and the OS would then avoid them. At least that's how I think it works.

SMART would probably identify these sectors as "pending reallocation". A subsequent format may cause the drive to reallocate these sectors or return them to service if they retest OK.


Well then people should be more precise as 'scanning program' is too ambiguous.

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 Post subject: Re: Best way to mark Bad Blocks on 1TB NTFS Disk?
PostPosted: February 1st, 2022, 12:13 
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Joined: July 2nd, 2011, 14:16
Posts: 453
Location: England
rec wrote:
cancunia wrote:
Apologies if this is already covered, please post a link if so.

I have a 1TB Samsung SATA hard drive on USB that I use for non critical copies & general work with read errors on a part of the disk and want to mark that area of the disk as 'bad blocks' , or whatever the correct terminology is, so that data does not get written to that area in future.
I had the idea of mounting the drive in a laptop and then booting from a USB stick and running something to scan & mark the bad areas on the disk. I'd prefer to keep the data on the disk intact, but can make backups & restore if needed to get a good result.
I would normally throw away a disk with errors, but as it's 1TB, even 90% is very useful.

Any ideas on what tools I can use? I can use Windows or Linux, not particularly fussed.

Thanks


Your strategy is useless as it won't protect you against data loss.

When writing to a drive with defective sectors, defective sectors will be remapped as long as there are spares available.
So there is no use for your procedure when writing.

So you are only left with reading your drive. You can check your existing files on your broken drive if they are readible. Once reading a drive fails your operating system will probably update it's list of bad blocks. But the data is gone anyway. And when deleting the file and upon reallocation of the freed sectors/blocks/clusters the remapping will hide the defective sector anyway once the next write transaction occurs.

What will happen when faced with pending and/or reallocated sectors is that they use to grow. You will notice that once you are unable to read files that were able to read before.

As you are probably not doing backups as well, the present community of data recovery specialists hear will gladly try to recover your lost information for a hefty multiple of the price of a new and healthy drive.

Personally I don't understand why people are so keen on playing roulette with their drive.
Are those people extremely poor and cannot afford buying a new drive? But how come they own a computer?

If you want to play roulette, regularly monitor your SMART parameters.


Thats quite realistic but morbid way of looking at it, but you do have a point.


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 Post subject: Re: Best way to mark Bad Blocks on 1TB NTFS Disk?
PostPosted: February 4th, 2022, 0:15 
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Joined: June 17th, 2019, 21:15
Posts: 117
Location: Homeroom
Here a strategy that can works... to avoid writing on problematic zone:
https://forum.hddguru.com/viewtopic.php?f=1&t=40671

The idea is to re-partition between the defective zones.
Use that if you cannot refurb your drive with a specialized tool.

The problem with chkdsk is it will not mark the weak sectors that are probably going to fall UNC soon.


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 Post subject: Re: Best way to mark Bad Blocks on 1TB NTFS Disk?
PostPosted: February 4th, 2022, 4:42 
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Joined: May 13th, 2019, 7:50
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Ow wow, excellent idea!! You know I have this great method for saving an entire drive! I make 4 drive RAID5, then once initialized I remove one disk because it will run fine with 3 drives too!! :D :D

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