You could check out
Monitorix. It creates pretty graphs for CPU load, HDD, Network activity etc.. You can configure it so you can view multiple systems at-a-glance, like this:
A live demo is available
here
Be aware that you need to install additional packages like rrd-perl etc., which are not available with the default Clear OS repositories.
You can check out my previous post on the subject if you are interested:
http://www.clearfoundation.com/component/option,com_kunena/Itemid,232/catid,26/func,view/id,12089/#1
Otherwise, you could set up a monitoring service like Nagios or Cacti if you want even more customized and advanced monitoring.