Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have a problem with drive cloning. Im using dd on damaged disk with bad sectors trying to make an image from it. Im booting computer with Live Linux CD .

Damaged disk: sda 146GB (NTFS) External drive: sdb 300GB (NTFS)

After running the command below im running out of space on disk sdb.

dd if=/dev/sda of=/media/sdb1/hdd.img bs=4096 conv=noerror,sync

The question is why im running out of space on disk sdb ?

UPDATE: There is 300 GB of free space on partition sdb1

share|improve this question
To be clear, you do have 146G of space available on sdb, right? – nickgrim Sep 7 '12 at 10:33
Yes, I have 300GB of free space on disk sdb – Alan Kuras Sep 7 '12 at 11:21
It is okay, that your sdb drive has 300 GB capacity, but your sdb1 partition has also enough free space for that image file? – Eddie Sep 10 '12 at 8:23
Can you add the output of df -h? – Joel E Salas Sep 10 '12 at 8:28
Yes because there is only 1 partition on disk sdb (whole 300GB) – Alan Kuras Sep 10 '12 at 8:46

/dev/sdb is a device special that represents the disk drive; it isn't a filesystem, but you've tried to use it as one.

Instead, try this:

dd if=/dev/sda of=/dev/sdb bs=4096 conv=noerror,sync
share|improve this answer
I dont want to clone drives one to one, i want to clone sda to image file (because sdb is USB disk drive). Im changing the question since it could be misunderstood. – Alan Kuras Sep 7 '12 at 9:36

I'm not sure, but it looks to me like a problem in NTFS driver (problem with large files).

Did you mount the NTFS partition using ntfs-3g? Also, could you provide us with full dd output?

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.