I've got relatively big filesystem (ext4) with lots of small files and I'd like to backup it. Making full backups often is not feasible to me so I want to have a way to make differential/incremental backups (differential preferred).
But... this is laptop, and scanning for changed files takes lots of time. My questions:
1) Is it possible to get list of files changed since some date from ext4's journal? I know it wasn't designed with this idea in mind, and it might be too small for bigger timespans, but maybe it is somehow possible?
2) Is it possible to monitor filesystem modifications and maintain a list of changed files reliably? I think I could use inotify, but this might be too slow to monitor full filesystem and might be unreliable. (by reliable I mean either I get all modifications since last backup (and this list is not missing anything) or an error message).
Laptop runs Debian unstable.