Add the following to /etc/rsyslog.conf after '$ModLoad imuxsock' and '$ModLoad imjournal':
$IMUXSockRateLimitInterval 0
$IMJournalRatelimitInterval 0
Set the following in /etc/systemd/journald.conf:
Storage=volatile
Compress=no
RateLimitInterval=0
MaxRetentionSec=5s
Restart journald and rsyslog to pickup the changes with:
systemctl restart systemd-journald.service
systemctl restart rsyslog.service