Also, it can be a nice trick to take a fs-structure dump: list of all files on disk, with associated sizes, permissions, and md5 hash. It should be much smalle

Also, it can be a nice trick to take a fs-structure dump: list of all files on disk, with associated sizes, permissions, and md5 hash. It should be much smaller (and faster) to take such a snapshot, but priceless if you ever suffer corruption for e.g identifying & verifying inodes, restoring permissions etc. Also useful for identifying which files are vanilla (same as installed from package) so can be restored by other means (finding original package). For that reason, a dump of installed packages w/ version is also useful.