I wrote a shell script recently that sends memory, cpu and hard drive statistics to firebase.com every minute via a cronjob and a simple front end site to display the results in angularjs 1.x - for such few connections, firebase is free.
I run it on 7 of our servers and it's helped nicely
The shell script could easily have more added to it (status of httpd or nginx, mysql, etc...)
I leave it running on a 2nd monitor all day and with the data binding of firebase / angularjs it refreshes automatically so i just watch it out of the corner of my eye.
I could throw it on git for you if you think it would help you.