[systemd-devel] [ANNOUNCE] systemd 219

[Joonas Sarajärvi]

2015-02-18 12:07 GMT+02:00 Lennart Poettering <lennart at poettering.net>:
> On Wed, 18.02.15 06:22, Andrei Borzenkov (arvidjaar at 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. As journal performance has already been
sufficient for my needs on btrfs, I would prefer to be able to
configure journald so that it'd keep the journal files with default
flags.

-Joonas