Systemd journal getting very large on 18.04 - how to reduce?

[Tom H]

On Sun, Aug 5, 2018 at 7:20 AM Chris Green <cl at isbd.net> wrote:
> On Sun, Aug 05, 2018 at 01:16:25AM +0200, Oliver Grawert wrote:
>> Am Samstag, den 04.08.2018, 20:38 +0100 schrieb Chris Green:
>>>
>>> I have an Ubuntu 18.04 system and I've just noticed that the
>>> /var/log/journal directory is 4Gb, that's way too much.
>>>
>>> How is it supposed to be limited.
>>
>> typically logrtate should cover it and rotate and compress it regulary,
>> if this does not happen then there is a bug you should report.
>> (the switch to journald-only-by-default is new in 18.04, someone might
>> have missed something)
>
> The journald.conf(5) man page tells me that the limit *is* 4Gb! That
> seems crazy to me, who wants 4Gb of journal files?
>
> The rules (for 'real' disk based journal files) are:-
>
> Maximum of 10% of the file system where /var/log/journal is
> Must leave at least 10% of file system free
> Absolute maximum of 4Gb
>
> These might make sense where /var/log is on a relatively small
> separate file system but I'm sure most Ubuntu users won't be in this
> situation (like me) and thus one will always hit the 4Gb absolute
> limit.
>
> It just doesn't sound sensible to me.

And, in a year, someone'll say that whatever value you consider
sensible isn't sensible...

You can control journal files with "SystemMaxUse" "SystemKeepFree"
"SystemMaxFileSize" "SystemMaxFiles" in journald.conf"..