FreeBSD の apache の log rotate.
/etc/newsyslog
に
#
/var/log/munin-node.log 644 7 * @T00 Z /var/run/munin/munin-node.pid
/var/log/www/httpd-access.log 644 10 * $W0D0 J /var/run/httpd.pid 30
/var/log/www/httpd-error.log 644 10 * $W0D0 J /var/run/httpd.pid 30
を追加