On Wed, 18.02.15 12:13, Joonas Sarajärvi (m...@iki.fi) wrote: > 2015-02-18 12:07 GMT+02:00 Lennart Poettering <lenn...@poettering.net>: > > On Wed, 18.02.15 06:22, Andrei Borzenkov (arvidj...@gmail.com) wrote: > > >> > >> btrfs checksumming theoretically allows you to transparently recover > >> after media corruption if filesystem has redundancy (more than one copy > >> of data). Journald checksum will probably detect corruption, but can it > >> repair it? > > > > No it cannot. > > > > But btrfs checksumming cannot fix things for you either if you lose > > non-trivial amounts of data. It might be able to fix a few bits of > > errors, but not non-trivial amounts. I mean, that's a simple property > > of error correction codes: the more you want to be able to correct the > > longer must your checksum be. Neither btrfs' nor journald's are > > substantial enough to correct even a sector... > > > > Lennart > > > > My impression is that btrfs can fix the corruption in cases where a > e.g. a RAID1 of btrfs is used.
FS_NOCOW does no effect btrfs raid settings. If you want this kind of data redundancy then it will continue to be available even though we set FS_NOCOW now. Lennart -- Lennart Poettering, Red Hat _______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel