How to deal with an Unrecoverable area

[rpodric]

I have a 1TB spinning Toshiba which for the better part of a year has been going between 0 and 8 for the SMART "Current Pending Sector Count" line. When it's on 8, any program attempting to use that area will have problems.

I figured this would be something for Spinrite 6.1, so I ran Level 3 on it but Dynastat could do nothing with those sectors and marked them with a U.

I really would like to get them out of the way though which I think could be done surgically (just these specific 8 sectors) using this technique:

https://forums.grc.com/threads/unrecoverable-errors-on-old-ssd-but-still-runs-do-anything.1691/#post-12661

But for one thing that I don't understand: every time I run Spinrite, the unrecoverable sector range changes slightly. It's always right near the start of the disk, but for example, one time it's sectors 5,998,368-375, the next time it's 6,043,256-263 etc

Is that expected? I was thinking that if there were 8 bad sectors, which definitely seems to be the case, they wouldn't be moving around. Given that they do, I have no idea how to employ the above dynastat 0 procedure then.

 

[DanR]

I really would like to get them out of the way though which I think could be done surgically (just these specific 8 sectors) using this technique:
https://forums.grc.com/threads/unre...d-but-still-runs-do-anything.1691/#post-12661

Correct.

But for one thing that I don't understand: every time I run Spinrite, the unrecoverable sector range changes slightly. It's always right near the start of the disk, but for example, one time it's sectors 5,998,368-375, the next time it's 6,043,256-263 etc

Do the bad sector numbers ever repeat?

Is that expected? I was thinking that if there were 8 bad sectors, which definitely seems to be the case, they wouldn't be moving around.

They should not be moving around. That suggests a possible serious problem with the drive.

dynastat 0 procedure

Given that you are considering a DynaStat 0 scan I presume the data on this drive is either backed up or of little consequence?
DynaStat 0 makes no attempt to recover data. So when an unreadable sector is found data loss will occur.

 

[rpodric]

Do the bad sector numbers ever repeat?

Not sure about ever, but I've tried it about 4 times and it's different each time.

They should not be moving around. That suggests a possible serious problem with the drive.

I wonder if SR leaving it as a "U" is a further clue to the stability of the disk. I was expecting originally that it would make quick work of it. especially since the relocated sector count is 0 (with a max of 95 apparently)..

Given that you are considering a DynaStat 0 scan I presume the data on this drive is either backed up or of little consequence?
DynaStat 0 makes no attempt to recover data. So when an unreadable sector is found data loss will occur.

It's a data drive, and the one file that would be affected is not a worry. If I ever needed whatever it is I could always get it from a backup.

 

[DanR]

OK then, there is nothing to lose!

The trouble spot appears to be right around the 0.2% point.

So, I would suggest a Level 2 DynaStat 0 scan from either 0 to 1 percent or from 0 to 21000000 sectors. That will go beyond the apparent trouble spot by a presumably sufficient margin to catch any problems? Then try a level 3 scan again.

The DynaStat 0 scan will put a list of any reallocated sectors in the SRLOG file for the run.

With a normal Level 2 or 3 scan SpinRite will go to great lengths to read a difficult to read sector. With DynaStat 0 however, SR reads once, and reallocates if the read is not successful.

 

[rpodric]

That sounds like a plan. Maybe I'll run it a few more times normally to see if I can narrow it a bit more though.

I overlooked the real intent of "dynastat 0," forgetting that it was only going to obliterate what it can't read. not everything in the range.

 

[PHolder]

I overlooked the real intent of "dynastat 0,"

It translates to: make zero effort at recovery on any failed read.

 

[cschuber]

I have a 1TB spinning Toshiba which for the better part of a year has been going between 0 and 8 for the SMART "Current Pending Sector Count" line. When it's on 8, any program attempting to use that area will have problems.

I figured this would be something for Spinrite 6.1, so I ran Level 3 on it but Dynastat could do nothing with those sectors and marked them with a U.

I really would like to get them out of the way though which I think could be done surgically (just these specific 8 sectors) using this technique:

https://forums.grc.com/threads/unrecoverable-errors-on-old-ssd-but-still-runs-do-anything.1691/#post-12661

But for one thing that I don't understand: every time I run Spinrite, the unrecoverable sector range changes slightly. It's always right near the start of the disk, but for example, one time it's sectors 5,998,368-375, the next time it's 6,043,256-263 etc

An unrecoverable area or bad sectors that change or dance around is an indication that the write heads are weak or bad. You're advised to copy your data off the drive to another.

AFAIK, Spinrite can't copy one drive to another. As a FreeBSD user when I encounter this I use one of two apps: ddrescue or dd_rescue.They work like traditional dd but skip over unreadable sectors. Recovering some of the drive is better than nothing. I don't know if there's a Windows app like this. You could probably use Clonezilla for this as it comes with ddrescue.

I haven't had to do this for a good number of years since I now mirror my ZFS and UFS filesystems.

Is that expected? I was thinking that if there were 8 bad sectors, which definitely seems to be the case, they wouldn't be moving around. Given that they do, I have no idea how to employ the above dynastat 0 procedure then.

If they move around, suspect your drive's write heads.