[systemd-devel] Merging journal logs from btrfs snapshots

[Kai Krakow]

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.

HTH
Kai