Does Cacti poll hosts in parallel or serial?

Question

Does Cacti poll in parallel or serial?

Answer 1

In a default polling scenario, where a single instance of poller.php is called by a cronjob, hosts are polled in serial. This is partially why it is normally not recommended to reduce the polling interval to be less than 5 minutes - since polling many hosts can sometimes take a substantial amount of time.

If you have a need for high-frequency polling, or polling in parallel, you should look at spine (formerly cactid) which runs as a daemon and is more highly configurable than poller.php in a cronjob. Or, you can configure multiple pollers to run in parallel, but if you're going to bother setting that up, might as well just configure spine