I/O Errors on dd an...
 
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I/O Errors on dd and dcfldd

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(@jsanders)
Active Member
Joined: 16 years ago
Posts: 11
Topic starter  

Greetings all! I've run this scenario past a couple folks on twitter and we're scratching our heads.

I've got a 60gb Hitachi drive that is going south on me. No problem, I'll dd the drive and restore to a good drive. Well, I start the dd and it gets to the same sectors every time and just grinds to a halt. I've run the dd command as followsdd if=/dev/sdc of=/mnt/bigdrive/hitachi_60.dd conv=noerror,sync bs=512
I have also tried dcfldd. It runs up to the same spot and then proceeds to tell me dcfldd /dev/sdc Input/output error
2939840+2463 records in
2942303+0 records out

The records in and out are incrementing so I'm thinking progress is being made, but I'm just not sure. Plus, I thought dd and dcfldd were supposed to just make a bit-by-bit copy and when bad sectors came along, it would pad those sectors with NUL's? Not spend hours trying to read the bad sectors.

I've let this job run for 36-48 hours and it just can't seem to make it past this spot. Is dd/dcfldd working as intended and should I just let it run for a week?


   
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(@patrick4n6)
Honorable Member
Joined: 16 years ago
Posts: 650
 

Try using a dd program that compensates for errors such as ddrescue.


   
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(@jsanders)
Active Member
Joined: 16 years ago
Posts: 11
Topic starter  

Running ddrescue now. Still choking on same spot. Guess I just have that many bad sectors and ddrescue is at least attempting to read each and every bad sector which takes time I guess.

Thanks Patrick for the input!


   
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(@farmerdude)
Estimable Member
Joined: 20 years ago
Posts: 242
 

Have you attempted reverse sector cloning?

Cheers!

farmerdude

www.onlineforensictraining.com

www.forensicbootcd.com


   
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(@jsanders)
Active Member
Joined: 16 years ago
Posts: 11
Topic starter  

I have not tried Reverse Cloning and don't know much about it. Perhaps I need to study up.

However, the good news is that ddrescue has moved past the bad sectors and is now halfway through the image. Looks like I may have some degree of success after all.


   
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(@douglasbrush)
Prominent Member
Joined: 16 years ago
Posts: 812
 

Media Tools Professional is a software tool that can perform reverse-cloning and cycle-cloning.

Basically reads from the end of the media to the beginning.


   
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(@miket065)
Estimable Member
Joined: 21 years ago
Posts: 187
 

Use the "noerror" option.

dd if=/dev/hdc of=largedisk.dd conv=noerror,sync


   
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(@jsanders)
Active Member
Joined: 16 years ago
Posts: 11
Topic starter  

noerror,sync was used. See first post. )


   
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(@mscotgrove)
Prominent Member
Joined: 17 years ago
Posts: 940
 

One approach I use is Incremental imaging

http//www.cnwrecovery.com/html/damaged_disks.html


   
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(@miket065)
Estimable Member
Joined: 21 years ago
Posts: 187
 

Ah, didn't see it because of the Ad…


   
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