[systemd-devel] Merging journal logs from btrfs snapshots

[Mirco Tischler]

Am 16.01.2014 22:15 schrieb "Chris Murphy" <lists at colorremedies.com>:
>
>
> On Jan 16, 2014, at 1:58 PM, Kai Krakow <hurikhan77 at gmail.com> wrote:
>
> > Chris Murphy <lists at colorremedies.com> schrieb:
> >
> >> Due to anti-magic, a recent update horribly broke the system's ability
to
> >> do further updates. This is resolved by regression to a prior Btrfs
> >> snapshot, once updated it works fine. But that's a two week old
snapshot.
> >> I don't need the broken rootfs but I want to keep the journal for those
> >> two weeks.
> >>
> >> Is this a reasonable want or need and if so how to merge the logs?
Between
> >> the two snapshots there are several like named files in
> >> /var/log/journal/<machine-id>.
> >
> > I'd recommend to place /var/log/journal on a subvolume so it is not
affected
> > by snapshotting. You can do separate snapshots for it (tho I cannot
imagine
> > why you would want to do it). That way you get a snapshot "protection"
for
> > these files, too, and you are free to roll back the rest of the system
> > without affecting this subvolume.
>
> Aha, good idea. So then I mount the subvol at /var/log/journal? Is there
any risk of journald writing to rootfs /var/log/journal before the
subvolume is mounted? Or is the flush to persistent storage sufficiently
delayed as to not be a concern?
>
> Chris Murphy
>
Afair, you don't need to mount subvolumes.

Mirco
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freedesktop.org/archives/systemd-devel/attachments/20140116/13673b9e/attachment.html>