New
#11
One question. If a drive is failing, corrupted data, etc., wouldn't "cloning" the drive result in the same corrupted data on the new drive?
Best method/tool for cloning a failing HDD for Data Recovery?
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New #12
I just had a quick run-through with Trinity Rescue kit. It will perhaps be too much for a non-Linux user. That is my first impression.
So then, I have come to the best way to clone a failing HDD sector by sector atleast for now :))
Tool: ddrescue Source: SystemRescueCD
1. Download the SystemRescueCD from Download - SystemRescueCd systemrescuecd-x86-4.2.0.iso 380MB and create a bootable pendrive with that ISO using Rufus Rufus - Create bootable USB drives the easy way
2. Boot your computer with that pen drive with your source disk (your failing disk) and a destination disk (formatted empty disk of capacity not less than that of your source disk) plugged in.
3.Against the command prompt type: fdisk -l [ENTER] This will list all your drives. Note the nomenclature of your source disk and destination disk.
4. Next against the command prompt type: ddrescue -r3 -n -S -v /dev/sdb /dev/sdc recovery.log [ENTER]
Note: Replace sdb and sdc with the correct device nomenclature of Source disk and Destination disk as obtained in step 3.
5. Sit back and relax. The cloning process may take days depending upon how bad your Source disk is. If your data is important patience is the key and the wait worth it. The saving grace is you can stop the process any time with Ctrl -C and then restart. It will take the cue from the log file and start from where it left.
In the cloning process itself it will go through cloning all the good sectors first and then try to recover the bad sectors one by one trying it 3 times (r3 option) before giving up on it.
I have actually tried it cloning an 8GB pen drive with bootable Peppermint Linux ( that was created sometime back on a request from Golden to try it and report ) onto a 32GB freshly formatted pen drive. It took about half an hour. At the end of the cloning I was able to boot into Peppermint from that cloned drive which signified successful sector by sector cloning including the boot sector/s.
May be Anshad Edavana will be able to polish it and improve upon it as one who had actually tried it on a failing disk. ( As indicated already I had no failing disk.)
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New #13
As you stated, a sector by sector copy will take several hours to complete. If the drive surface is really bad, probably it will take days. I might have some spare failed drives to experiments further. I will report back once my attempt to duplicate a real bad drive is finished.
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New #14
The logic behind disk cloning and attempting data recovery on that cloned drive:
When a disk starts failing, further deterioration can be fast and it can die any moment. Subjecting it to a data recovery process straight away may accelerate it. Also if one data recovery process fails, we recommend another data recovery procedure. This repeated use may further accelerate the deterioration. So the normal recommendation is use it only once and that to clone the drive so that one catches as much good data as possible. Also the algorithm of these data rescue cloners is entirely different than the algorithm used by the conventional imaging/cloning software used for back up or so we are told. Anyway that should be evident the way ddrescue works. During the first run it grabs all the good and readable sectors ensuring no further data loss. Next it tries to read the bad sectors one by one and retrieve the data in it. But generally if within three passes no data on it can be recovered it is given up as irrecoverable. The option r3 defines that 3 passes. With r1 it will be infinite number of bad sector recovery passes.So it is actually a clone+recovery process. On a cloned drive one can try any number of data recovery process to retrieve whatever data it could without any fear since it is a good drive.
OK, I do know that a failing drive has to show up first if you want to clone. If you have one such drive you may try. Also since my "failed drive" was in fact a good drive, I did not find any recovery.log file in the root directory of the drive from which I ran the System Rescue. So I haven't tried Stop and restart process.
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New #15
Hi
For anyone interested, i will share my experience in cloning a failing 80 GB HDD to a 160 one. My first experiment is to check whether "Macrium" can clone this drive successfully but as i expected "Macrium" failed to clone.
Then i booted the system using "Parted magic" and issued fdisk -l command to list the connected disk's details. sda is the 80 GB source drive, sdb is the target drive and sdc is the USB flash drive to store the log file ( The drive connected to SATA port 1 will be named "sda" , second one will be "sdb" ).
I used the command line ddrescue -d -f -r3 /dev/sda /dev/sdb /media/sdc1/Log/rescue.logfile
Option d is to tell DDrescue to use direct disk access, option r3 is for specifying the maximum number of read attempts when it encounter a bad sector and f is to specify block copy operation.
The cloning operation took roughly 45 minutes which is not bad for a sector to sector copy. In the end "DDrescue" managed to clone everything except 3584 bytes which is around 3.5 KB.
If the drive surface contain hundreds of bad sectors, cloning operation may take several hours and the total read error ( total number of bytes which can't be copied ) will be bigger. However we may be able to rescue a portion of the data without much damage.
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New #16
That's a good show and proves beyond doubt that ddrescue is the best tool to clone a failing hard drive.
Can you now try running ddrescue from Systemrescuecd (my post #12) and with this command set?
root# ddrescue -r3 -n -S -v /dev/sda /dev/sdb recovery.log
-r3 = retry the damaged areas in 3 passes
-n = Skip the splitting pass. Avoids spending a lot of time trying to rescue the most difficult parts of the file.
-S = Sparse mode. May save a lot of disk space in some cases.
-v = Verbose mode. Shows all the details about what's happening.
/dev/sda = the source drive
/dev/sdb = the destination drive
recovery.log = The name of the log file.
EDIT:In this case the recovery.log file should be available in the root directory of the drive from which ddrescue is run and would not require a third drive. In such a case it will be easy for the user to stop and then restart the cloning procedure and there will be no need for the user to search and plug in any third drive on which the log file will reside.
When I ran this command to clone my failing disk ( in fact a good pen drive
)I had some problem with -S option, so I think I went ahead with the same command set but without the -S option that resulted in successful cloning. I still do not know the significance of -S.I did notice the direct disk access option -d but did not involve it.Also you may put a screenshot of the recovery.log file.
Thank you for trying it out on a failing disk (the real life situation) and sharing the information.
May be it will now be necessary to decide upon the best options (command set for an effective recovery) What we now know is it works and it will be safe to use.
Last edited by jumanji; 20 May 2014 at 21:38.
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New #17
Hi jumanji
Unfortunately i returned the 80GB failing HDD to it's customer. However it is not difficult for me to find another one. There are some other command line options i also wanted to experiment with. I will report back with the result later ( may take a couple of days ).
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New #18
You may take your time. No problems.:)
In the meanwhile, I have marked this thread as solved and in future ddrescue will be the tool that we will recommend ( atleast I will recommend with confidence :)) in the case of failing hard drives to clone and then run any data recovery procedures.
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New #19
Just a few minutes ago I stumbled on this and am surprised :
The very same question I had asked in my first post, appears verbatim in Yahoo! answers https://ph.answers.yahoo.com/questio...0235401AAWGH3E and without a name or person who raised the query and seeking answers.
This seems to have been posted about two hours ago when I was busy shopping groceries in a nearby department stores.
I am surprised how this could happen and hours prior to that I had marked it as solved in this Forum.
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New #20
Hi
Finally got two more drives to play with "ddrescue" but unfortunately both of them are severely damaged and far beyond the capability of "ddrescue". However i spend a lot of time lurking through various forums and read opinions of those who are using "ddrescure" for years. Here is my conclusion.
1. Generally it is not advised to directly clone a failing HDD to another one.Different hard drives may have different sector sizes ( 512 native, 512e, 4096 native etc ) which may cause issues. It is always better to take an image of the source disk - sector size of target disk won't matter. Almost all data recovery tools available today supports directly working with disk images ( including TestDisk, Photorec , Getdataback , R-Studio etc ).
2. Cloning an MBR partitioned disk to a similar or larger capacity drive will work as long as sector sizes are equal. If in doubt, use HDParam which is included with almost all Linux based rescue discs to obtain the details of connected hard drives.
3. Directly cloning a GPT partitioned disk requires the target disk to be with same exact LBA numbers.For example if the source disk has 1000 sectors, the target drive should be a 1000 sector drive - a 1001 sector drive won't work. This is because GPT stores a backup partition table on the very last sector and if that is absent, disk will be shown as unpartitioned in most cases. Creating disk image is the best practice when dealing with a GPT partitioned disk.
4. Avoid using USB enclosure and connect disk drives directly. If the source disk or destination disk is a proprietary external drive which can't be dissembled and directly connected to an internal port, avoid cloning and always take a full disk image.Last edited by Anshad Edavana; 16 Jun 2014 at 10:59.
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