On Tue, May 7, 2019 at 11:17 AM Nik. <bt...@avgustinov.eu> wrote: > > It took about 18 hours to compare the mounted volume with the backup > (used rsync, without the "--checksum" option, because it was too slow; I
If you're comparing without --checksum, it's just checking file size and timestamp. It's not checking file contents. > can run it again with it, if you wish). Only about 300kB were not in my > backup. Given the backup is also on a btrfs system, is there a more > "intelligent" way to compare this huge tree with the backup? Not if you have reason to distrust one of them. If you trust them both, comparison isn't needed. So you're kinda stuck having to use a separate tool to independently verify the files. >Optimally > the fs would keep the check-sums and compare only them? No such tool exists. Btrfs doesn't checksum files, it checksums file extents in 4KiB increments. And I don't even think there's an ioctl to extract only checksums, in order to do a comparison in user space. The checksums are, as far as I'm aware, only used internally within Btrfs kernel space. -- Chris Murphy
