December 19, 2006 · Backup · Email This Post

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dd_rhelp is a bash script that handles a very usefull program written in C which is called dd_rescue, it roughly act as the dd linux command with the caracteristic to NOT stop when it falls on read/write errors.

This makes dd_rescue the best tool for recovering hard drive having bad sectors.In short, it'll use dd_rescue on your entire disc, but will try to gather the maximum valid data before trying for ages on badsectors. So if you leave dd_rhelp work for infinite time, it'll have the same effect as a simple dd_rescue. But because you might not have this infinite time , dd_rhelp will jump over bad sectors and rescue valid data. In the long run, it'll parse all your device with dd_rescue.

You can Ctrl-C it whenever you want, and rerun-it at will, it'll resume it's job as it depends on the log files dd_rescue creates.In addition, progress will be shown in a ASCII picture of your device beeing rescued.

Why use dd_rhelp and not dd_rescue ?

dd_rhelp uses dd_rescue to compute a recovery path through the device that will focus on valid data recovering. This recovery path will go through all the device, exactly as dd_rescue could do it on its own without any path. This means that dd_rhelp will save you time ONLY IF YOU INTEND TO CANCEL ITS JOB BEFORE THE END of a full recovery.

Because a considerable amount of time is taken to try to rescue badsectors. This amount of time can be mesured in days,
month, years, depending on your device capacity and its defectiveness. You might not want to spend this time knowing that 99 percent of this time will be taken to look at badsector and won't lead to any more data recovering.

dd_rhelp shifts this useless waiting time to the end. Using dd_rescue strait throughout your device make your waiting time dependent on the badsector distribution.

Install dd_rhelp

First you need to download latest version from here

Preparing your system

sudo apt-get install make gcc g++ ddrescue

Download dd_rhelp using the follwoing command

wget http://www.kalysto.org/pkg/dd_rhelp-0.0.6.tar.gz

Now you have dd_rhelp-0.0.6.tar.gz file

Extract this file using the following command

tar xzvf dd_rhelp-0.0.6.tar.gz

cd dd_rhelp-0.0.6

Run the following commands

sudo ./configure

sudo make

sudo make install

This will complete the installation and this will install program under /usr/local/bin/dd_rhelp

dd_rhelp Syntax

dd_rhelp {filename|device} {output-file} [{info}]
or dd_rhelp --help
or dd_rhelp --version

Now we will see how to use ddrescue under damaged disk

If you have a damaged hard disk /dev/sda1 and you have an empty space hard disk /dev/sda2 Now if you want to copy data from /dev/sda1 to /dev/sda2 use the following command

sudo dd_rhelp /dev/sda1 /dev/sda2/backup.img

Output looks like below

/usr/bin/tail: Warning: "+number" syntax is deprecated, please use "-n +number"
=== launched via ‘dd_rhelp' at 0k, 0 >>> ===
dd_rescue: (info): ipos: 104384.0k, opos: 104384.0k, xferd: 104384.0k
errs: 0, errxfer: 0.0k, succxfer: 104384.0k
+curr.rate: 10178kB/s, avg.rate: 8532kB/s, avg.load: 31.3%
dd_rescue: (info): /dev/sda2 (104391.0k): EOF
Summary for /dev/sda2 -> backup.img:
dd_rescue: (info): ipos: 104391.0k, opos: 104391.0k, xferd: 104391.0k
errs: 0, errxfer: 0.0k, succxfer: 104391.0k
+curr.rate: 355kB/s, avg.rate: 8519kB/s, avg.load: 31.3%
/usr/bin/tail: Warning: "+number" syntax is deprecated, please use "-n +number"

This copies an image of /dev/sda1 to sda2

Now you need to check the backup image consistency this will check for is there any problems with this image.

sudo fsck -y /dev/sda2/backup.img

After finishing this checking you need to mount your disk image in to your other hard disk

sudo mount /dev/sda2/backup.img /mnt/recoverydata

This will mount all the data from the backup.img under /mnt/recoverydata now you can try to access the data it should
work without any problem.

Restore image

If you want to restore this image use the following command

sudo dd_rhelp /dev/sda2/backup.img /dev/sda1

Copy Disk Image to remote machine using SSH

If you want to copy your disk image to remote machine over ssh you need to use the following command

sudo dd_rhelp /dev/sda1 -- | ssh username@machineip ‘cat /datarecovery/backup.img’

This will be prompetd for password of the username you have menctioned in the above command after entering the password

dd_rhelp strats copying obviously it will take some time to copy over the network.

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13 Comments to “Recover Data from a Damaged hard disk using dd_rhelp”

  1. Adam Collett says:

    Thank you SO much for this, I have just managed to recover my whole movie collection using this method. I had spent over three weeks getting all my DVD’s onto hard disk and then the file system went – after eventually finding somewhere with enough space I used this method, created an image file of the drive and then FSCK’d it and bingo – mounted it and there were all my films! I can’t tell you how pleased I am with this – I will be getting a RAID-1 setup now so that should something go wrong with a drive again I won’t have this problem – and I shall be backing up to a seperate physical device too!

    [Reply]

  2. shriganesh says:

    hi
    this is ganesh, i have problem with my HDD. i have downloade the dd_rhelp but i could not install it bcoz i could not under stand it. so kindly hepl me to retrive the datas.

    [Reply]

  3. Rodney Rundstrom says:

    I have carried out the proceedure as listed by you and it went without any flaw however when I try to run dd_rhelp it tell THAT MY TARGET IS NOT ACCESSABLE. I have tried two other partions with the same result. I am using Ubuntu 9.04

    [Reply]

  4. Zubair says:

    Hi, can any 1 help me, I have did a mistake. I make reverse copy from backup disk to source disk. how can i undo this step because distination data copied to source disk. I want to bring back my source data.
    Plz any one help me ASAP.
    Zubair.

    [Reply]

  5. MANOJ SHUKLA says:

    My hard disk hit by me.It is not working, gone dead position.System in o position hard disk sound is kit kit kit ……………and do not start/detect any partition or any data. I want to recover 70GB data.What can I do? please help me.

    [Reply]

  6. Djaffar says:

    Mr Manoj Shukla, I’m in the same shit like you, my daughter slamed my HDD and now it does the same sound as yoursand doesn’t start, from what I read in the net I thing it’s bad news buddy! really physical damaged HDD (like motor heads..)can’t be recovered by conventional recovery sofware but could be done by a specialized tech and some time not 100% all of data could be recovered?! well I’m still trying I hope I can find a solution.

    [Reply]

  7. Ajay says:

    Manoj/Djaffar, even i too have the same problem. Really i dono how it went wrong in the HDD. Nearly after a week when i switched on my sys some creepy noise came from CPU and found its from HDD :( .
    Can anything be done to recover the Data from HDD, can any one help me in this as i have few important data to be recovered.

    -Ajay

    [Reply]

  8. Britti says:

    Great post.Thanks so much for the post.I have managed to recover some of my lost files from my HDD.I was so lucky and after getting them back,i rushed and backed them up online with safecopy backup among my other files.With safecopy,they keep deleted files forever and now am so happy that i go a new HDD and my account with safecopy backup has been upgraded.

    [Reply]

  9. prajyendu says:

    You change your RAM then it will work properly or replace your ram

    [Reply]

  10. Chris says:

    Finally found this post, many thanks, one of the better dd_rhelp run throughs on the net.
    One question though if anyone can help, is it possible to run dd_rhelp in the following configuration:
    dd_rhelp /dev/sda2 /dev/sdb2
    Intention being to directly copy a damaged HDD partition to a new disk with an equal size partition (bypassing any image files). I have had this running for a day or so now and it doesn’t complain when the command is submitted, but I dont want to wait a week to find it wasn’t actually writing anything, so if anyone knows for sure that this wont work I will stop and start again with an image file intermediate step.

    Many thanks,

    [Reply]

  11. shashidhar says:

    i’v got bad sectors on hard disk and it gets detected in bios but fails to move further…..i need to retrieve myn 40gb drive wht to do?

    [Reply]

  12. subham says:

    I want to recover my 80 gb HDD its not working.
    But during startup its showing secondary device failure…Pl help me in solving this problem

    [Reply]

  13. aya says:

    i have no idea how to extract this dd_rhelp-0.0.6.tar.gz file using tar xzvf dd_rhelp-0.0.6.tar.gz? can anyone tell me how to do it?please?

    [Reply]

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