I'm recovering data from a damaged 500GB disk drive. I'm copying data (ext4 partition) to a 500GB image file. The process is taking about 3 months of copying in total (yes, months). So I'm using
dd for patiently filling the image file. First I dd a chunk to a temp file, then put the chunk into the backup file and so...
The problem is that I want to access the partially filled image and recover some data before the backup process ends. I've mounted it read-only and used
testdisk and it's ok. But I also want to try
fsck to (try to) repair the partition. After peeking data I would like to rollback fsck changes and resume the copying.
I know tools like
git derivates (
git-annex...) that could help. but I wonder if there is a way to make this in-place. Not taking another 500Gb of indexed original data.
I don't want versioning capabilities. I don't want a backup of my file. The workflow would be something like:
- I have
original_500GB_file.img-> 500GB of data
- I modify 2GB of the file. Say now I have
modified_500GB_file.imgand other auxiliary files -> less than 600GB of data (500 original + 2 modified + some metadata)
- When I'm happy making changes, rollback and get to point 1 again.
How can achieve this? Would it be possible with BTRFS snapshot capabilities?? (unfortunately I have the file in a NTFS partition)