Welcome to the forum guys.
Yup; here have started to play a bit with CollectD and RRD Tool. Relating to at home firewalls stuff have played with Smoothwall and DD-WRT. Most recently have started to play with OpenWRT installing it a few devices to get familiar with it.
Today using PFSense which does include metrics with RRD.
I do currently have collectd and rrdtools running and haven't broken anything so far. Thing is I cannot see the graphs yet.
I did also install multiple interfaces on my PFSense box relating to load balancing and multiple firewall testing which provides a non dependant means of testing the Almond +.
Suggesting if you want to play some more install some collectd modules, rrdtool and the luci stuff to see the graphs.
I have the tools working fine on another OpenWRT build...
Broke my Almond + this morning (not really though).....issues relate to ties to LCD GUI to currently implemented themes. That said looking now to play with the LCD GUI to break it some more....maybe even put mini graphs on the LCD gui (just to see if I can do it).