file recovery from 1 TB exernal drive

Using PhotoRec to recover lost data
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boxerab
Posts: 2
Joined: 11 Jul 2021, 22:13

file recovery from 1 TB exernal drive

#1 Post by boxerab »

Hello,
I have an external drive formatted as NTFS, and I was viewing it recently
from my linux machine. I may have done a very dumb thing - deleted a System Info
directory on the drive. Now I can't open the drive : testdisk tells me the file system
is damaged and can't be mounted.

I ran photorec and did recover some files - however, estimated time for full recovery
was 1000 hours. Is there a way of speeding photorec up? I am a software developer,
so I would be happy to work on this. I guess reading a disk is a very serial process,
but is there a way of making use of more threads? I have 48 on my system.

Thanks,
Aaron

recuperation
Posts: 1497
Joined: 04 Jan 2019, 09:48
Location: Hannover, Deutschland (Germany, Allemagne)

Re: file recovery from 1 TB exernal drive

#2 Post by recuperation »

boxerab wrote: 11 Jul 2021, 22:18 Hello,
I have an external drive formatted as NTFS, and I was viewing it recently
from my linux machine. I may have done a very dumb thing - deleted a System Info
directory on the drive. Now I can't open the drive : testdisk tells me the file system
is damaged and can't be mounted.

I ran photorec and did recover some files - however, estimated time for full recovery
was 1000 hours. Is there a way of speeding photorec up?
As you did not state what kind of drive and what size you are referring to I can't tell you if that is slow.
Compare your current speed to the sustained native speed of your drive or drive array.

I am a software developer,
so I would be happy to work on this. I guess reading a disk is a very serial process,
but is there a way of making use of more threads? I have 48 on my system.
The first thing to check is to check the drive health using smartmontools.
See:
viewtopic.php?f=5&t=10910

If your drive is dammaged duplicating the drive using ddrescue as described in the manual would speed up the process.

If you want modify the code of Photorec in such a way that a couple of worker threads are doing the job simultaneously the disk input/output will the bottleneck, I assume.
In such a case using a SSD as a source would heal the speed issue.

Please provide Christophe Grenier with any code modifications or additional code.

Thank you.

boxerab
Posts: 2
Joined: 11 Jul 2021, 22:13

Re: file recovery from 1 TB exernal drive

#3 Post by boxerab »

Thanks, @recuperation. This is an external spinning rust
WD My Passport drive. Running testdisk, it appears that the disk
itself is damaged. My strategy is now to run ddrescue to copy
the disk image, and then run photorec on the image.

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