r-studio + ddrescue + map file

A forum on data recovery using the professional data recovery software R-STUDIO.
thetoad
Posts: 5
Joined: Sat Jul 03, 2021 4:40 am

r-studio + ddrescue + map file

Post by thetoad » Sat Jul 03, 2021 4:52 am

It doesn't seem like r-studio can make use of ddrescue's map file. This could be useful for letting a user have confidence that data was recovered fully from a disc imaged with ddrescue.

ddrescue's map file would tell you if a block was read or not (if the all 0s in the file block on the file system are meant to be there or not). I think this would be a useful feature for you to add to the system (unless I was blind and didn't see that it was already there)

edit: other features that could be useful for r-studio if supporting ddrescue

generating a "fake" map file to enable ddrescue to focus on metadata blocks (i.e. directory entry) information vs actual data blocks (i.e. file content). i.e. if what I'm calling a metadata block is damaged, even if the content of the file is there, one won't be able to recover, by creating a "fake" map file, a user can focus on recovering those area (i.e by pretending the other areas are good). One would then want a utility to combine the original, the faked and the update of the fake into a new map file the is accurate to what was recovered

similarly, one could do the same for individual files, "I only want to recover the data for file X, generate me a map file that enables me to focus on that file" similarly, one can combine that in and generate a new map file.

edit 2: apparently someone asked about this a few years ago viewtopic.php?f=13&t=10829&p=16111&hili ... cue#p16111

I'm guessing as nothing has happened, its not really something that will happen :(

edit 3:

and actually I learned something new. one wouldn't have to create new map files that would then be "integrated", one could simply create what ddrescue calls a domain mapfile that marks all the data that one doesn't currently care about as "read" and marks everything that we want as unread. this doesn't overwrite the original map file which would continue to be used, but would enable one to have ddrescue focus on the blocks that matter at the moment.

I really feel this would be useful for people to recover data in a better way. r-studio provides the ntfs / fs knowhow in general, ddrescue provides the bit moving brawn.
Last edited by thetoad on Sat Jul 03, 2021 9:02 am, edited 1 time in total.

Alt
Site Moderator
Posts: 2765
Joined: Tue Nov 11, 2008 2:13 pm
Contact:

Re: r-studio + ddrescue + map file

Post by Alt » Sat Jul 03, 2021 9:02 am

thetoad wrote:
Sat Jul 03, 2021 4:52 am
It doesn't seem like r-studio can make use of ddrescue's map file.
I'm guessing as nothing has happened, its not really something that will happen :(
A little bit of patience. But no strict date promised.

thetoad
Posts: 5
Joined: Sat Jul 03, 2021 4:40 am

Re: r-studio + ddrescue + map file

Post by thetoad » Sat Jul 03, 2021 9:05 am

ah, you responded just when I was editing, see my last update. being able to output a domain mapfile from rstudio to target metadata (Say mft) or specific files, could be a massive win in consumer data recovery (at least for the technically incined)

while rstudio might be able to do all of what ddrescue can do, ddrescue has the main advantage that i can easily run it on a headless machine (i.e. just ssh in and image a disk)

Alt
Site Moderator
Posts: 2765
Joined: Tue Nov 11, 2008 2:13 pm
Contact:

Re: r-studio + ddrescue + map file

Post by Alt » Sat Jul 03, 2021 9:09 am

thetoad wrote:
Sat Jul 03, 2021 9:05 am
while rstudio might be able to do all of what ddrescue can do, ddrescue has the main advantage that i can easily run it on a headless machine (i.e. just ssh in and image a disk)
R-Studio for Windows + RDP = a headless machine

thetoad
Posts: 5
Joined: Sat Jul 03, 2021 4:40 am

Re: r-studio + ddrescue + map file

Post by thetoad » Sat Jul 03, 2021 9:26 am

in my case, right now, I'm working on recovering a 10+ year old archive disk that seems to have had what I'd classify as "magnetic bit rot". i.e. if it seems physically fine (no clicking, 99.9% of the disk has been read, all but about 15MB), but 2.5MB of what isn't read is in the MFT (inode 0, per ddru_findbadntfs). And r-studio shows the same X's through the files/directories that are causing problems to be read, when I mount the "lossy" image I've already made

thetoad
Posts: 5
Joined: Sat Jul 03, 2021 4:40 am

Re: r-studio + ddrescue + map file

Post by thetoad » Sat Jul 03, 2021 9:28 am

Alt wrote:
Sat Jul 03, 2021 9:09 am
thetoad wrote:
Sat Jul 03, 2021 9:05 am
while rstudio might be able to do all of what ddrescue can do, ddrescue has the main advantage that i can easily run it on a headless machine (i.e. just ssh in and image a disk)
R-Studio for Windows + RDP = a headless machine
yes (in a past life, I worked at MSFT on the RDP team), but in all honesty, its easier for me to run the rescue on my linux box which is meant to be up 24/7 and is in what is essentially my home server closet than my windows boxes which are in places where people sleep.

thetoad
Posts: 5
Joined: Sat Jul 03, 2021 4:40 am

Re: r-studio + ddrescue + map file

Post by thetoad » Sat Jul 03, 2021 1:31 pm

as an example, a directory under the root was corrupted (512 bytes weren't read), and this seemed to prevent it from a) showing up in a mount and even r-studio wasn't enumerting it correctly. so while ddru_ntfsfindbad is far from perfect, it was able to help me identify the blocks that defined the directory. I then created a domain map to enable ddrescue to focus on that area, and it showed the 512byte block that it hadn't read, with the ability to focus on it, after about 10-20 read attempts, it was able to copy it into my image file and when mounted, the whole directory and its contents appeared and were able to be copied out.

the same can happen with r-studio today, even when one does a full scan (which can take a whole day on a large hard drive), if directories are corrupt, it wont be able to associate the files to the directory, by giving us the ability to say "these are the block I need so you don't have orphaned files", it would improve data recovery ability. This isn't as big a deal if files are all named uniquely. However, if you have directory after directory of files all named the same (say datasets where the directory is what made them unique) it can be difficult to untangle all the same named files and recovering the directory can be important.

abolibibelot
Posts: 40
Joined: Sun Jan 31, 2016 5:45 pm
Location: France

Re: r-studio + ddrescue + map file

Post by abolibibelot » Wed Sep 15, 2021 8:00 pm

generating a "fake" map file to enable ddrescue to focus on metadata blocks (i.e. directory entry) information vs actual data blocks (i.e. file content). i.e. if what I'm calling a metadata block is damaged, even if the content of the file is there, one won't be able to recover
Not true, “raw” recovery is still possible in that situation, provided that the file was not fragmented.
similarly, one could do the same for individual files, "I only want to recover the data for file X, generate me a map file that enables me to focus on that file" similarly, one can combine that in and generate a new map file.
That would make sense only if NOT running a complete scan with R-Studio (since the whole purpose of doing such a “surgical” recovery would be to reduce the stress and strain to a minimum), so that would make sense only when the filesystem structures are not damaged at all, but another specific area is damaged. That would still make sense, but that would be a rather advanced feature, probably reserved for the most expensive version. (From what I've read, another cloning application can do something similar in combination with another recovery application -- but only with a “pro” license.)
being able to output a domain mapfile from rstudio to target metadata (Say mft) or specific files, could be a massive win in consumer data recovery (at least for the technically incined)
Targetting the $MFT with ddrescue : you can already do that with ddru_ntfsbitmap, part of ddr_utility (from the same author as HDDSC, although no longer supported this bunch of complimentary tools for ddrescue still works wonders).
but 2.5MB of what isn't read is in the MFT (inode 0, per ddru_findbadntfs)
Well, apparently you already know about ddr_utility...

Post Reply