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Is it too late to backup after bad sectors are found?

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August 23, 2010 5:02:44 PM

Hi All, I bot WD 500GB black 1 week ago and turns out to be a defective one, had trouble reading/copying files sometimes,did CHKDSK and WD data lifeguard diagnostic. CHKDSK shows 4-5 msgs that "windows replaced bad clusters in file xxx" and DLD just stops and gives error msg "too many bad sectors"

I already installed a lot of stuff on my disk and seems everything else is running as normal - at least now. My questions are :

1 . Can I still use acronis true image WD edition to make a backup?

2. In backup acronis will probably have same hard time when hit those bad sectors, but i read the manual it actually can skip the bad sectors. The problem now is if there are some crucial files on bad sectors and acronis doesn't backup them, the new system won't work out i guess.

3. if i choose to backup whole things - including files on bad sectors. Will those bad sectors brought to my new hard drive? or just corrupted files are brought?

the bottom line is to keep the new hard drive free from those bad clusters and save my time rebuilding the system.

THanks a lot!
August 23, 2010 6:53:50 PM

Better to backup.
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a c 342 G Storage
August 23, 2010 7:56:53 PM

A backup software tool would be better than a cloning tool like Acronis True Image. If you do clone a file that contains a bad sector, the clone copy will NOT have a "bad sector" from a hardware view; it will just contain corrupt data in that part of the file.

When such problems arise, the message from CHKDSK usually tells you which file name was using each bad sector it replaced. Then you know that you now have a corrupted version of that file on your HDD and you need to replace it with a known-good version of the file somehow. But my guess is you never noted down those file names, so now you don't have any record of which files need replacement.

I assume that your plan is to save all your data through a backup, then replace the bad drive under warranty. Right?
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August 23, 2010 8:58:41 PM

Thanks, yes that's what i am trying to do. I asked the same question to WD support and here is their answer:

" Unfortunately if there are bad sectors they will be move to the new drive. We do not suggest using Acronis if the source disk is defective or with errors."

I am bit confused b/c what you said is more intuitive.

And actually there are 4-5 msgs of "replaced bad clusters" in CHKDSK, the issue is i ran data lifeguard diagnostic after CHKDSK is completed and still stuck and end up with error msg "too many bad sectors" - DLD didn't finish the scanning just stopped. Shouldn't the CHKDSK already replace and fix the bad sectors? why there are still there? How can i tell they are logical bad sectors or physical bad sectors?

Appreciated!



Paperdoc said:
A backup software tool would be better than a cloning tool like Acronis True Image. If you do clone a file that contains a bad sector, the clone copy will NOT have a "bad sector" from a hardware view; it will just contain corrupt data in that part of the file.

When such problems arise, the message from CHKDSK usually tells you which file name was using each bad sector it replaced. Then you know that you now have a corrupted version of that file on your HDD and you need to replace it with a known-good version of the file somehow. But my guess is you never noted down those file names, so now you don't have any record of which files need replacement.

I assume that your plan is to save all your data through a backup, then replace the bad drive under warranty. Right?

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a c 415 G Storage
August 24, 2010 2:15:01 AM

Paperdoc is right in that the disk you're copying TO won't end up with bad sectors as a result of the copy - all that will happen is that you won't get the correct data for the sectors that couldn't be read from the bad drive.

But if the bad drive has bad sectors in critical areas such as the Master File Table or in a folder, then it may prevent you from getting certain files at all. In this case neither a backup program nor a cloning tool will be able to help.

Frankly, if your drive is only a week old I think you'd be better off just to forget about what's on it and start over again from scratch. Otherwise there's always going to be some doubt about whether the files you recovered from the drive might contain corrupt sections or not.

...and hopefully you learn from this to make regular backups to avoid worrying about how to get your data back in the future.
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August 24, 2010 3:59:55 AM

Thanks sminlal, i already request a replacement. somehow i m lucky that i found the problem before it's too late - i found it when downloading files, it stuck there having trouble writing and the files downloaded cannot be used so I ran CHKDSK to find the problem.

So when i receive the new harddrive, i will run CHKDSK right after I install the windows, i think this protects me from using a defective one w/o awareness. is that a good idea? Or the bad sector doesn't come with the harddrive, instead of, happens after using?



sminlal said:
Paperdoc is right in that the disk you're copying TO won't end up with bad sectors as a result of the copy - all that will happen is that you won't get the correct data for the sectors that couldn't be read from the bad drive.

But if the bad drive has bad sectors in critical areas such as the Master File Table or in a folder, then it may prevent you from getting certain files at all. In this case neither a backup program nor a cloning tool will be able to help.

Frankly, if your drive is only a week old I think you'd be better off just to forget about what's on it and start over again from scratch. Otherwise there's always going to be some doubt about whether the files you recovered from the drive might contain corrupt sections or not.

...and hopefully you learn from this to make regular backups to avoid worrying about how to get your data back in the future.
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a c 342 G Storage
August 24, 2010 3:15:53 PM

With a brand new HDD I usually don't bother with these precautions, assuming that it will be completely good. BUT, as your tale proves, that is NOT always the way it goes.

CHKDSK is actually not the best tool for this. You are better to use the Data Lifeguard tool you already have. For more ocmplete details I'll refer you to two earlier posts I made:

http://www.tomshardware.com/forum/254149-32-level-forma...
http://www.tomshardware.com/forum/259141-32-help-please...

They both start out from a question on formatting, etc, but the info on the background workings of the controller board on the HDD unit itself is what I'm referring to. The key is to recognize that, by forcing a Zero-Fill operation using Data Lifeguard on the entire HDD, you will also trigger its own hidden sector substitution system so that there are NO "bad sectors" available. Now, since this works on the entire drive, it takes a long time! And when you're done, the HDD is completely blank and must have new Partition(s) Created and Formatted. (Of course, if you're Installing Windows on it at this point, the Partitioning and Formatting are done by the Install process anyway - no need to do it yourself.) And NOTE that the default version of Formatting here is the Full Format which actually does at least a read-check of every sector that Windows can access, which is the same as a CHKDSK operation later.

AFTER the HDD is Partitioned and Formatted and Windows is running, you can run CHKDSK if you want - with its long process - any time. But also you can use Data Lifeguard to check the HDD. There are a few tools that do NON-destructive tests on the drive and check the SMART data for indications of impending problems. These tools are not included in what CHKDSK does. Just do NOT run the Zero-Fill operation - it DOES destroy everything as it writes zeroes everywhere.
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August 24, 2010 4:08:23 PM

I tried to do the extended test in DLD and it stopped working by giving me error msg "too many bad sectors" , so I doubt it can do the 0-fill test? Maybe i should try. The other ways are format in the windows and format in Bios, which is better way? since I have to wipe out everything b4 i ship it back.

Another question about 0-fill is, since i have no idea they are logica or physical bad sectors and 0 fill can only fix the logical bad sectors. I was also told even if it's fixed it tends to have problem again soon, is that right?

As for CHKDSK i don't think it's doing a good fixing job, since i did DLD after CHKDSK still got that error msg.

Thanks a lot!



Paperdoc said:
With a brand new HDD I usually don't bother with these precautions, assuming that it will be completely good. BUT, as your tale proves, that is NOT always the way it goes.

CHKDSK is actually not the best tool for this. You are better to use the Data Lifeguard tool you already have. For more ocmplete details I'll refer you to two earlier posts I made:

http://www.tomshardware.com/forum/254149-32-level-forma...
http://www.tomshardware.com/forum/259141-32-help-please...

They both start out from a question on formatting, etc, but the info on the background workings of the controller board on the HDD unit itself is what I'm referring to. The key is to recognize that, by forcing a Zero-Fill operation using Data Lifeguard on the entire HDD, you will also trigger its own hidden sector substitution system so that there are NO "bad sectors" available. Now, since this works on the entire drive, it takes a long time! And when you're done, the HDD is completely blank and must have new Partition(s) Created and Formatted. (Of course, if you're Installing Windows on it at this point, the Partitioning and Formatting are done by the Install process anyway - no need to do it yourself.) And NOTE that the default version of Formatting here is the Full Format which actually does at least a read-check of every sector that Windows can access, which is the same as a CHKDSK operation later.

AFTER the HDD is Partitioned and Formatted and Windows is running, you can run CHKDSK if you want - with its long process - any time. But also you can use Data Lifeguard to check the HDD. There are a few tools that do NON-destructive tests on the drive and check the SMART data for indications of impending problems. These tools are not included in what CHKDSK does. Just do NOT run the Zero-Fill operation - it DOES destroy everything as it writes zeroes everywhere.

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August 24, 2010 6:01:06 PM

I guess I was not clear about WHICH drive to work on. I agree that, if Data Lifeguard says there are too many errors to bother continuing, it is NOT worth your time to try "fixing it". Get a replacement. Now, IF you really want to clear off any data on the unit before retuning it, a Zero-Fill by Data Lifegaurd will do that. It does NOT work through Windows' access to the HDD. It works at a lower level directly with the controlled on the HDD and it will write zeros to EVERY sector of the HDD that is supposed to be OK. Then it will read to check the sector condition, and will try to substitute good sectors for those it finds bad. But for your purposes, the important part is that ALL of the sectors get over-written, destroying any old data.

The reason I raised the Zero-Fill option in the first place was for use with the NEW replacement unit. I normally would NOT do this on a new HDD. BUT since you've already had a very bad experience, if you want to be especially cautious you can run a Zero-Fill operation by Data Lifeguard on the empty brand new drive to be absolutely sure that ALL of its available sectors are good. THEN you proceed with using it normally.

A Zero-Fill done by the HDD's controller board is NOT the same as anything that Windows can do, and this includes the "zero-fill" type of thing that newer Windows Format operations do. The HDD has its own controller on board and Data Lifeguard uses that to do its Zero-Fill to every sector. (Well, to be precise, the HDD's board also has some hidden spare good sectors it will use to replace any found bad, and I'm not completely sure any of those would be filled by this.) However, that board hides all those lower-level details from the OS. All Windows can know is that the HDD tells it that it has all these sectors available and can use them. Windows, in its File System data structures, keeps its own separate set of records about the use of sectors available to it, and one of the things it can do is mark a sector as "bad" so it is not used, and replace it with another that is not yet in use. But it is still only working with the sectors that the HDD let it see - Windows knows absolutely nothing about the secret stash of spare "good sectors" that the HDD's own board controls.

Be aware also that, when Windows runs CHKDSK and makes its own decisions and replacements, it does NOT have any way to tell the HDD's own board about all this. So if there really is a bad sector that Windows decides to mark off and never use, and then you run the DATA Lifeguard tests, that latter utility will still find the SAME bad sector that Windows found and now refuses to use. But the result is different. When the HDD's board finds it, it replaces it with a good sector from its spare pool. Now the sector is good. But Windows does not know this, and still believes it is never to be used!
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August 24, 2010 7:32:27 PM

I see.. now it's pretty clear. long story short, The 0-fill operation does fix the bad sectors but CHKDSK doesn't.

The tricky part is DLD can only be installed and ran after windows is installed, so it will erase the windows in windows ( in my situation i need to format os w/o installing new os)? If i do this for the new replacement unit, i will have to install windows twice.

Theoritically i don't have to do the replacement, since no matter return it or keep using it I will do the 0-fill anyway and after that the hard disk is healthy with all bad sectors fixed. Not saying i could receive a same defective hd from WD if i am unlucky



Paperdoc said:
I guess I was not clear about WHICH drive to work on. I agree that, if Data Lifeguard says there are too many errors to bother continuing, it is NOT worth your time to try "fixing it". Get a replacement. Now, IF you really want to clear off any data on the unit before retuning it, a Zero-Fill by Data Lifegaurd will do that. It does NOT work through Windows' access to the HDD. It works at a lower level directly with the controlled on the HDD and it will write zeros to EVERY sector of the HDD that is supposed to be OK. Then it will read to check the sector condition, and will try to substitute good sectors for those it finds bad. But for your purposes, the important part is that ALL of the sectors get over-written, destroying any old data.

The reason I raised the Zero-Fill option in the first place was for use with the NEW replacement unit. I normally would NOT do this on a new HDD. BUT since you've already had a very bad experience, if you want to be especially cautious you can run a Zero-Fill operation by Data Lifeguard on the empty brand new drive to be absolutely sure that ALL of its available sectors are good. THEN you proceed with using it normally.

A Zero-Fill done by the HDD's controller board is NOT the same as anything that Windows can do, and this includes the "zero-fill" type of thing that newer Windows Format operations do. The HDD has its own controller on board and Data Lifeguard uses that to do its Zero-Fill to every sector. (Well, to be precise, the HDD's board also has some hidden spare good sectors it will use to replace any found bad, and I'm not completely sure any of those would be filled by this.) However, that board hides all those lower-level details from the OS. All Windows can know is that the HDD tells it that it has all these sectors available and can use them. Windows, in its File System data structures, keeps its own separate set of records about the use of sectors available to it, and one of the things it can do is mark a sector as "bad" so it is not used, and replace it with another that is not yet in use. But it is still only working with the sectors that the HDD let it see - Windows knows absolutely nothing about the secret stash of spare "good sectors" that the HDD's own board controls.

Be aware also that, when Windows runs CHKDSK and makes its own decisions and replacements, it does NOT have any way to tell the HDD's own board about all this. So if there really is a bad sector that Windows decides to mark off and never use, and then you run the DATA Lifeguard tests, that latter utility will still find the SAME bad sector that Windows found and now refuses to use. But the result is different. When the HDD's board finds it, it replaces it with a good sector from its spare pool. Now the sector is good. But Windows does not know this, and still believes it is never to be used!
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a c 342 G Storage
August 25, 2010 3:53:18 AM

AH! We come to one of my favorite points. Go back to the WD website and get a DIFFERENT version of Data Lifeguard (and, I think, a better one). Look for the one called Data Lifeguard for DOS. This one runs WITHOUT Windows! There are two versions - one for making a bootable floppy disk, and another for making a bootable CD-ROM disk, which is probably the one you want.

http://support.wdc.com/product/download.asp?groupid=612...

READ the instructions on that page before downloading - maybe print it out. Within the CD-ROM version there are two sub-versions. One is an .iso image file - a complete image of what needs to be on the CD_ROM you will burn. The other is a .zip file that just contains the .iso file compressed so it's faster to download, but requires un-zipping. Once you have the .iso file, you then need a CD burning utility like Nero that can burn a CD from a .iso image file.

So, with the newly burned CD, you place it in your optical drive, make sure the BIOS is set to boot from that drive, and power up. The machine will boot from the CD and load a mini-DOS into RAM, then run the diagnostic utility package menu system. You can run all of its tests and its repair tools from the main menu. This all works with NO functioning HDD in your machine, and NO need to load and run the Windows OS.

Remember, SOME of the diagnostic routines (like zero-fill) CAN destroy data, so watch for the messages that warn you of such impending actions.

NOTE: the Zero-Fill operation does NOT solve your problems with a drive that does have big hardware trouble. From what you describe, your HDD seems to have MANY bad sectors, and that means it SHOULD be replaced under warranty now.

In my other posts I referenced earlier, I pointed out that, when a HDD is made, the spare stock of good sectors is noted in a storage system on the HDD's controller board. When that board, in the normal course of operations, detects a bad sector it tries hard (and usually succeeds) to read the data from there and copy it to one of the good spare sectors, then makes the substitution. This "fixes" the bad sector as far as the user is concerned. But it does NOT really. Eventually if lots of bad sectors are found and replaced, the stock of spares is depleted and that's one type of message you can get through the SMART warning system. This means that, if the process continues much longer, there will be no good spares left and it can't fix itself any more. BEFORE that happens you must replace the HDD.

In your case, it really sounds like there are 'way too many bad sectors already and the unit should be replaced under warranty now, not later. This is another place where Data Lifeguard for DOS is vital! If you ask for a warranty replacement, WD Tech Support will tell you to run Data Lifeguard on the unit and report to them the results of the tests. That way they can tell exactly what is wrong and whether a replacement is justified. So, get the diagnostic tool, run the tests, and write down the results. You will need them.
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August 25, 2010 11:59:38 PM

Thank you so much! the answer makes a lot of sense to me! However had i seen your post earlier i would do that do what you are saying. .. I already format the old HDD using windows boot disk (and it only takes few seconds which surprised me, i guess it just simply erases all the stuff) and receive the new HDD. WD doesn't need the result they ship me a new one pretty fast and wait to receive my old one.

you know what...i am running DLD extended test right after i installed the windows now and it's almost done seems everything is OK. At least can i say the HDD comes good and free released? Or i need to test for how long...




Paperdoc said:
AH! We come to one of my favorite points. Go back to the WD website and get a DIFFERENT version of Data Lifeguard (and, I think, a better one). Look for the one called Data Lifeguard for DOS. This one runs WITHOUT Windows! There are two versions - one for making a bootable floppy disk, and another for making a bootable CD-ROM disk, which is probably the one you want.

http://support.wdc.com/product/download.asp?groupid=612...

READ the instructions on that page before downloading - maybe print it out. Within the CD-ROM version there are two sub-versions. One is an .iso image file - a complete image of what needs to be on the CD_ROM you will burn. The other is a .zip file that just contains the .iso file compressed so it's faster to download, but requires un-zipping. Once you have the .iso file, you then need a CD burning utility like Nero that can burn a CD from a .iso image file.

So, with the newly burned CD, you place it in your optical drive, make sure the BIOS is set to boot from that drive, and power up. The machine will boot from the CD and load a mini-DOS into RAM, then run the diagnostic utility package menu system. You can run all of its tests and its repair tools from the main menu. This all works with NO functioning HDD in your machine, and NO need to load and run the Windows OS.

Remember, SOME of the diagnostic routines (like zero-fill) CAN destroy data, so watch for the messages that warn you of such impending actions.

NOTE: the Zero-Fill operation does NOT solve your problems with a drive that does have big hardware trouble. From what you describe, your HDD seems to have MANY bad sectors, and that means it SHOULD be replaced under warranty now.

In my other posts I referenced earlier, I pointed out that, when a HDD is made, the spare stock of good sectors is noted in a storage system on the HDD's controller board. When that board, in the normal course of operations, detects a bad sector it tries hard (and usually succeeds) to read the data from there and copy it to one of the good spare sectors, then makes the substitution. This "fixes" the bad sector as far as the user is concerned. But it does NOT really. Eventually if lots of bad sectors are found and replaced, the stock of spares is depleted and that's one type of message you can get through the SMART warning system. This means that, if the process continues much longer, there will be no good spares left and it can't fix itself any more. BEFORE that happens you must replace the HDD.

In your case, it really sounds like there are 'way too many bad sectors already and the unit should be replaced under warranty now, not later. This is another place where Data Lifeguard for DOS is vital! If you ask for a warranty replacement, WD Tech Support will tell you to run Data Lifeguard on the unit and report to them the results of the tests. That way they can tell exactly what is wrong and whether a replacement is justified. So, get the diagnostic tool, run the tests, and write down the results. You will need them.

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August 26, 2010 12:00:03 AM

Best answer selected by stonexu1984.
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a c 342 G Storage
August 26, 2010 6:05:10 PM

If the DLD Extended Test says your HDD is all good (or has a VERY few items it fixes), that's all you need. There is no reason to repeat the test now. You may find many months from now that you can do the Short or Extended tests again just to be sure no big new errors have shown up, but that is not common. Just use ONLY the tests that do NOT do any damage to your data.
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