Icinga2 is a great Network & Systems monitoring tool forked from Nagios. It's very flexible and very easy to understand and use. I have worked with many different Network and Systems monitoring tools throughout my career, Solarwinds, SCOM, WhatsUP Gold, ManageEngine, SpiceWorks, Nagios, etc. just to name a few. But this one beats them all.
If you can't find a plugin (or check as they call it in Nagios world), you can write your own and that's what I did. Go check it out, it's on github,
This lets you monitor Disk, RAID status, and NIC failures on your Overland Storage arrays.