journalctl/rsyslog pause/delay while logging

[Alex]

Hi,

I have a fedora23 mail server that's been working for quite some time.
I have rsyslog installed and configured to log mail to
/var/log/maillog. It's never had a problem, but for some reason
yesterday it started intermittently stop logging for about three
minutes, then catch up with the three minutes of missed data before it
begins to log normally again.

It then appears to log for another few minutes, then repeat this cycle.

Looking at the logs with "journalctl -f" shows no such lag with
logging, but I can't use journalctl for this project.

Any idea what could be causing this?