data recovery - How can I recover files from a part of a disk image?

data-recovery dd

05
2014-04

Panagiotis

I am backing up a dying hard drive using dd. Unfortunately the process is taking very long (95KB/s) and I would like to see if I can get some of my files from the part that is already copied (~26GB). I used scalpel and I managed to recover a small part of files, mostly jpeg images. I am afraid that this program finds files that I have deleted and not the ones that are actually still there. Are there any alternatives I can use?

I am trying to mount the already recovered part but it fails. Do I need to recover the whole disk before I can mount it?

Answers

Thomas W.

If dd is very slow, I expect that it tries to read faulty sectors many times. Finally it can even happen that dd fails.

I would recommend using dd_rescue. It is more intelligent regarding read errros. While it might not fully recover your data, it should still be faster and you're able to mount the image earlier.

When you can mount the image, you can simply access the files as they were before (given you have just read problems, not file system problems) and there is no need for Scalpel any more.

Related Answers

sleske

Your best bet is to restore from your most recent backup. You have backups, right? :-)

If you don't have backups and the drive isn't even recognized as existing when you plug it in you're probably in Data Recovery Company territory (also see Google: "Data Recovery Services"), and data recovery tends to get hideously expensive.
Out of the 3 linked I would recommend starting with Tekserve -- They deal with Macs regularly, and if they can't recover your data at their facility they may be able to refer you to someone who can.

Realistically unless the data on this disk is of super-critical business importance and was the only copy in the world recovery probably isn't worth the price. If it IS super-critical this is an expensive lesson in why you need to start backing up (If you're using a Mac I suggest using Time Machine: Mostly automatic & a good fit for 99% of users)

Bill Graefe

SpinRite sounds like a great solution until you find you have to have a PC to run it on your Mac disk. Additionally, it sounds like it works similarly to Gnu ddrescue (though with some additional logic that fills in missing data where it can). Tech Support for SpinRite said they didn't have any cases of their program running on Mac hardware which amazed me because I can boot a FreeDOS CD on my Mac (that's what they use but they said they require BIOS too). They did have some reports from users that it works in VMWare by booting an image of their CD.

Posipiet

Put a pricetag on your data.

If that number comes out four-digit, head to a professional Data Rescue Service near your location.

If the number comes out three-digit, find a local computer service who may try something out.

If it is two-digit, wave your data goodbye.

There are several ways in which a disk can die. Depending on what the failure consists of, your chances vary quite a bit.

Set up a proper backup, too.

djangofan

If you have a windows computer there is a bunch of freeware recover tools you can find at http://www.portablefreeware.com/index.php?p=2&q=recover which includes Recuva .

Also, you might try a bootable Linux rescue kit.