[systemd-devel] Journald retaining logs for only 10 days

[Lennart Poettering]

On Mo, 16.11.20 20:29, Andrei Borzenkov (arvidjaar at gmail.com) wrote:

> > Hu? As far as I can tell, I told it to keep 300 MB and it's using 320
> > MB.
>
> For all I can tell, SystemMaxUse applies to inactive journal files only
> - this sets target how many archived files to delete. systemd will
> switch to new file and archive current if currently active file exceeds
> max size. Max journal file size is by default set to 1/8th of max
> allowed space. Which means with SystemMaxUse=300M max journal file size
> is set to 37.5MiB and at any time you may have up to 300MiB of old files
> and one currently active file which may grow up to 37.5MiB. So 337.5MiB
> in total.
>
> And my understanding is that every user's journal adds to this - so
> basically you will have additionally 37.5MiB x number of active user
> sessions.
>
> If someone more familiar with journal internals will confirm it, it
> calls for documentation update. While manual page says "Also note that
> only archived files are deleted to reduce the space occupied by journal
> files" it does not make clear that limits effectively apply to archived
> files only and active files may additionally consume up to
> SystemMaxFileSize each before something triggers rotation.

Could you file an issue about this on github?

Note that there already is a note indicating that the use can grow
above SystemMaxUse=, but it should be updated about more than
SystemMaxFiles=. Quoting the man page journald.conf(5):

        SystemMaxFiles= and RuntimeMaxFiles= control how many
        individual journal files to keep at most. Note that only
        archived files are deleted to reduce the number of files until
        this limit is reached; active files will stay around. This
        means that, in effect, there might still be more journal files
        around in total than this limit after a vacuuming operation is
        complete. This setting defaults to 100.

Lennart

--
Lennart Poettering, Berlin