Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

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'm planning on using GNU ddrescue to create a drive image of my failing 1 TB hard drive. Can I store the image sufficiently on another 1 TB hard drive? I figure the answer would be no because the image file would contain header information which in addition to the disk-image itself should exceed the drive`s capacity (in a perfect world, but perhaps not?).

I would clone the drive, but I'm not sure how to make sure the clone isn't modified when booting up the OS (Windows or Linux).

share|improve this question
You can compress the image or use the --sparse option. – Marco Sep 11 '12 at 6:52
up vote 0 down vote accepted

In a perfect world it should fit, but your educated guess is mostly correct.

The problem with the --sparse option, is that "Not all systems support this. Only regular files can be sparse."

You can pipe ddrescue through gzip to compress the end file on the fly. Examples:

# backup
dd if=/dev/hdx | gzip > /path/to/image.gz

# restore
gzip -dc /path/to/image.gz | dd of=/dev/hdx

note that dd and ddrescue are interchangeable. They produce the same result using different techniques.

share|improve this answer

I would just clone the entire drive. Assuming the drive hasn't completely been toasted I would use dd_rescue.

fdisk -l to see which drive is which and then someting like the following from a live cd:

dd_rescue /dev/sda /dev/sdb

Assuming /dev/sda is the source (bad drive) and /dev/sdb is the destination.

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.