MAILTO=zerebubuth@gmail.com
# do the dump in the early hours of the morning and follow, if successful, by a cleanup of the old files. i don't think these are of any historical interest, so just keep three consecutive.
43 3 * * * www-data nice /usr/local/bin/rrddump > /srv/munin.openstreetmap.org/dumps/`date "+munin-data-%Y-%m-%d.tar.gz"` && ls -1 /srv/munin.openstreetmap.org/dumps/munin-data-*.tar.gz | sort -r | tail -n +4 | xargs rm -f