title: Linux journal daemon log and/or persist only the error/critical event logs
body: <p>With the systemd journal daemon is there a way to configure the persisted logs (/var/log/journal/*) so that only Errors and Critical level events are actually stored to disk?</p>
  <p>We have extremely high volume servers that would generated gigabytes daily in just kernel logging but as far as the journal goes we only really care for error/critical events.</p>
  <p>I've checked the manpage for /etc/systemd/journald.conf but there doesn't seem to be much there in the way of selecting which level of events persist (Or which levels to ignore in general)</p>
  <p>(<a href="https://www.freedesktop.org/software/systemd/man/journald.conf.html" rel="nofollow noreferrer">https://www.freedesktop.org/software/systemd/man/journald.conf.html</a>)</p>