Questions about Photorec used with ddrescue disk images

Using PhotoRec to recover lost data
Post Reply
Message
Author
Rodama
Posts: 2
Joined: 25 Oct 2012, 00:06

Questions about Photorec used with ddrescue disk images

#1 Post by Rodama » 25 Oct 2012, 02:08

Wanted to start off by saying that Christophe Grenier along with his Testdisk/Photorec programs are amazing. A few years ago I had a partition mangled by Diskeeper's piece-of-junk FAT32 boot defragging. With Testdisk, I was able to fully recover the partition with no issues, with some additional assistance from Mr. Grenier. His expertise is unquestionable.

The situation I'm in currently is a suddenly bad-sectored hard drive less than a year old (a Western Digital Cavier Green; if you have anything valuable to keep, buy a more reliable drive) that I am intending to recover data from to a brand new drive. The bad drive is 2TB in size (as is the new drive) with one NTFS (Windows XP) extended partition in one logical drive. Its data only.

Being a relatively advanced user, have done extensive research and decided in the end to use GNU ddrescue to clone the bad drive and then use Photorec on the recovered data if necessary. The decision to start with ddrescue was finalized by Mr. Grenier's recommendation at his link "Damaged Hard Disk".

Will be using the ddrescue included with the well known, free "SystemRescueCD" 3.0 Linux live CD. Am using that because its the only live CD I could find that includes the latest version 1.16 of ddrescue. I've also decided to make a disk image of the bad drive onto the new, good drive instead of a raw clone. Basically because I can then mount it in Windows with the free OSFMount and copy the good files off the image before using Photorec in Windows.

My questions regarding Photorec are as follows. According to its instructions, the recommendation is apparently: "To recover files from a media image, run photorec image.dd to carve a raw disk image". However, in making a ddrescue image, the names commonly recommended for disk images are "imagename.img", "imagename.dmg" and the like with three character extensions. Not two.

Does Photorec care what the disc image is named as on the good drive? Or will ddrescue care if I enter the image name as Photorec's instructions state as "image.dd"?

Here is the ddrescue string I intend to use to recover the undamaged data first (the volume names have been verified and will start in the directory on the new drive where the log file is going): ddrescue -n -v /dev/sda1 /dev/sdb2/baddata.img rescue.log

Then after that completes, run it again to recover more bad-sector data: ddrescue -r 3 -v /dev/sda1 /dev/sdb2/baddata.img rescue.log

Finally, will mount the disk image in Windows with OSFMount, check what I can copy, then use Photorec on the image, if possible. Once I know if the Windows version of Photorec (testdisk-6.14-WIP.win.zip) can read/use an image mounted like that and what image name I should give it when using ddrescue.

Thanks in advance for your help.

Sponsored links

User avatar
cgrenier
Site Admin
Posts: 3809
Joined: 18 Feb 2012, 15:08
Location: Le Perreux Sur Marne, France
Contact:

Re: Questions about Photorec used with ddrescue disk images

#2 Post by cgrenier » 29 Oct 2012, 07:59

Rodama wrote: My questions regarding Photorec are as follows. According to its instructions, the recommendation is apparently: "To recover files from a media image, run photorec image.dd to carve a raw disk image". However, in making a ddrescue image, the names commonly recommended for disk images are "imagename.img", "imagename.dmg" and the like with three character extensions. Not two.

Does Photorec care what the disc image is named as on the good drive? Or will ddrescue care if I enter the image name as Photorec's instructions state as "image.dd"?
The filename has no importance for PhotoRec and ddrescue as long as you are using the same for both tools.

Rodama
Posts: 2
Joined: 25 Oct 2012, 00:06

Re: Questions about Photorec used with ddrescue disk images

#3 Post by Rodama » 30 Oct 2012, 03:34

Thank you very much for replying with the helpful info.

I was imagining that Photorec wouldn't have a problem with image file names of various types that are the same, but its nice to know for sure.

One final quick question that has just appeared here before getting started. It has to do with ddrescue specifically, but hope it can be answered.

Searching through Google, have been unable to find any info on what sort of size the ddrescue log file averages. The bad drive here that's 2 TB in size was nearly full when it died: only 24GB free or so. I was planning to have the log file made on the same good drive (also 2 TB) that the disk image goes to.

What sort of size per GB of data recovered (or similar) would I be looking at for the log file? The reason am asking, of course, is concern that if the log gets too large, it will fill the limited space open on the new drive & interfere with recovering data with Photorec or otherwise. In which case it would be better to put it on a third drive, which would be a lot more inconvenient.

Thanks again in advance (and I promise that's my last question about this issue :)).

User avatar
cgrenier
Site Admin
Posts: 3809
Joined: 18 Feb 2012, 15:08
Location: Le Perreux Sur Marne, France
Contact:

Re: Questions about Photorec used with ddrescue disk images

#4 Post by cgrenier » 04 Nov 2012, 19:06

The log file is usually a few KB to one MB.

Post Reply

Who is online

Users browsing this forum: No registered users and 1 guest