I have been thinking about getting started with monitoring software for a while now, but never seem to get started with it well.
I have heard Nagios is a pretty decent open-source solution for this, but have never been able to properly get started with it.
Does anyone have any tips with some good approaches to getting started on server monitoring? I am thinking of things like number of network connections, load average, maybe bandwidth used by the server, etc. The basics involved, largely (which may include basics that I do not know about).