advice on speeding up recovery process

Using PhotoRec to recover lost data
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bartleby
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Joined: 26 Sep 2013, 01:49

advice on speeding up recovery process

#1 Post by bartleby » 10 Oct 2013, 20:10

I've been recovering data from a 3TB usb hard drive (western digital mybook). I accidentally knocked it off of a low shelf while it was reading or writing data. Partition tables are gone it seems and I am recovering data in the raw mode and photorec is building the files (over 20,000 files recovered so far). The process is very slow with an estimated 4500 hours left (I understand this may not be accurate). I've dedicated an older spare computer to do the recovery running linux from a live usb flash disk. The cpu on the machine is an 2.13 GHz Intel Core2 Duo Processor P7450 with 2gb ram. Question: Why don't I see much cpu or ram being used? The ram is typically about 2.5% with the cpu at around 0.3%. Is there anything that I might do to speed up this process? Photorec is returning good files so I am content to wait for the data but I worry about encoutering other drive problems if the recovery were to take many months.

I tried this too:
I have also tried removing the hard drive from the case and attached it to my pc via its sata interface but that resulted in errors due to western digital drives self encrypting so that they must be used with the usb controller board (bridge board) that that was used to write the data. Remember this the next time you are looking to buy an external usb hard drive. If the controller/bridge board fails or you just want to use the faster sata interface to recover your data on a newer model western digital external usb drives - you cannot. You must then spend a lot of money to have pro bypass the encryption and very few are capable of doing it. I'm not sure about other models from other mfrs. Here's a link to the western digital site with some info on the evil usb bridge board: http://community.wd.com/t5/Off-Topic-Di ... /true#M738

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cgrenier
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Re: advice on speeding up recovery process

#2 Post by cgrenier » 16 Oct 2013, 07:07

PhotoRec can be very slow if the source disk contains bad sectors. Remove all non-essential USB devices, use short USB cable, avoid USB hub, store the recovered data on a disk connected via SATA.
You can also clone the disk to a new empty one using GNU ddrescue as described in
http://www.cgsecurity.org/wiki/Damaged_Hard_Disk and once it's done, use PhotoRec on the clone.

bartleby
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Joined: 26 Sep 2013, 01:49

Re: advice on speeding up recovery process

#3 Post by bartleby » 16 Oct 2013, 07:26

I think photorec got past the point on the drive with the serious damage because it started to recover files very fast and the cpu was at approx 80% for about 25 minutes. Many more thousands of files recovered. Now it is slow again but sectors are being read at a consistent rate it seems. Perhaps it is at a part of the drive now where there was simply no files ever written. Now to sort and see what has been recovered.

nobootabledevice
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Re: advice on speeding up recovery process

#4 Post by nobootabledevice » 31 Jul 2014, 22:53

I have the same problem. It's been extremely slow for the past day or two. At this rate it would take 69 daysto complete according to my calculations. I'm hoping that this is just it going over bad sectors and it will speed up soon.

nobootabledevice
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Re: advice on speeding up recovery process

#5 Post by nobootabledevice » 01 Aug 2014, 09:19

It has been running ever since that post and has barely moved at all.

laerne
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Re: advice on speeding up recovery process

#6 Post by laerne » 10 Nov 2014, 20:59

I have a external hard drive whose partition MBR table and tables has been messed up with a fsck.ntfs process I have to kill. The hard drive is 1000GB NTFS. I'd like to fix the partition table and then quickly use fsck again, but it is so slow.

So I launched testdisk and it took a bout half an hour to display me the available disks to work on. I picked my external hard drive, and its menu has been freezing for three hours since then. I didn't get the partition table type selection menu yet (it's regular windowsy intel partitions). Is it reading the 1000GB to guess the partition table type ? How long am I supposed to wait a 1TB usb3 hard drive to complete in testdisk ? Will I have to reparse the whole disk again to fix the partition ? Is there speed-up option to use ?

Thank,
laerne.

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cgrenier
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Re: advice on speeding up recovery process

#7 Post by cgrenier » 11 Nov 2014, 09:16

There are probably bad sectors. You should clone your disk first using gnu ddrescue
http://www.cgsecurity.org/wiki/Damaged_Hard_Disk
Once it's done, discard the original disk and try to fix the partition on the new disk.

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