Subject: herd restart mcron appears to wipe /var/log/mcron.log

From: Robert Vollmert <[email-masked]>
Date: Mon, 8 Jul 2019 14:09:30 +0200

It appears that old mcron log output is lost when the service is
restarted. That’s not good.

See also https://debbugs.gnu.org/cgi/bugreport.cgi?bug=36510 for
another issue related to mcron logging.