Most rpm installations will setup the crontab entry now. If you've followed the installation instructions to the letter (which you should always do ;-) ), you may now have two poller running. That's not a good thing, though. Most rpm installations will setup cron in /etc/cron.d/cacti
Now, please check all your crontabs, especially /etc/crontab and crontabs of users root and cactiuser. Leave only one poller entry for all of them. Personally, I've chosen /etc/cron.d/cacti to avoid problems when updating rpm's. Mosten often, you won't remember this item when updating lots of rpm's, so I felt more secure to put it here. And I've made some slight modifications, see
shell> vi /etc/cron.d/cacti */5 * * * * cactiuser /usr/bin/php -q /var/www/html/cacti/poller.php > /var/local/log/poller.log 2>&1
This will produce a file /var/local/log/poller.log, which includes some additional informations from each poller's run, such as rrdtool errors. It occupies only some few bytes and will be overwritten each time.
If you're using the crontab of user "cactiuser" instead, this will look like
shell> crontab -e -u cactiuser */5 * * * * /usr/bin/php -q /var/www/html/cacti/poller.php > /var/local/log/poller.log 2>&1