I used dd to create a imagefile of a partition of my external hdd. I used the 'conv=noerror,sync' option to skip readerrors and it did a full copy.

'sudo dd if=/dev/sdd of="/media/me/out/theimage.img" conv=noerror,sync'

Now I noticed that fsck returns some errors on the source-disk /dev/sdd. I had fsck repair the disk, which went well.

Now the question is: Should I make a new imagefile? Could it be that dd missed some data due to corrupted filesystem or some such?

Or can I use fsck to fix the imagefile just like it fixed the disk?

Right now if I run fsck on the image file, it screams at me that there are issues with the filesystem...


You can do either: fix the image file or make a new one.

However, I would use ddrescue instead of dd as it was designed to be able to read bad sectores / skip over them / ...:

sudo apt install gddrescue
ddrescue --retry-passes=3 /dev/sdd /media/me/out/theimage.img /media/me/out/theimage.log

For more info: man ddrescue

  • Thanks. Ironically, ddrescue hangs on me... log: # current_pos current_status current_pass 0x6F3170000 ? 1 # pos size status 0x00000000 0x6F3180000 + 0x6F3180000 0xD4C6E80000 ? – bernd feinman Dec 19 '18 at 1:16
  • Read all of the documentation: you have a bad sector and it doesn't hang: it's trying to continue... – Fabby Dec 19 '18 at 1:16
  • 1
    How long can that take though? It's been stuck for at least 15 min. I'll let it run overnight. – bernd feinman Dec 19 '18 at 1:22

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