Sparse file question for data recovery

Sparse file question for data recovery

[Janos Haar]

Hello list,

It is a way to use sparse files (or sg. else) to try to recover some big
block device when it is readonly?

I mean the original device is marked readonly, and only the changes are
saved for the sparse file.
This is useful if i want to only try to repair corrupted (or miss-assembled)
raid arrays, image from damaged hdd, etc...

Like only save the "undo" information independently from the repairing
program.

I only know that with nbd-server, but i wish to use a simple local solution.

Somebody have an idea? :-)

Thanks,

Janos Haar