We're currently using Nagios to monitor about 20 Linux machines (services and functional links). I just find out about Munin and I wonder if this is a Nagios replacement, or it can be used together with Nagios? I don't want to spend hours setting it up, just to discover that I already have all that functionality with Nagios.
I'd especially appreciate if someone who used both programs can give some insight about your experience. Which is better for which task and what do you recommend to use?
Note: we also used Cacti for some time. The main problem we have with Nagios is that setup takes too long and isn't very straightforward.