Cluster Information for Virtualmin/Webmin

Hello everyone,

I am not sure if this is even the correct place for this but here it goes. I have been thinking about this for sometime and after 2 server issues that had my site along with some others down for a period of time. I decided to start loooking in to this seriously, so from what I am gathering so far there is no clear way to do this. So I was wondering one of you folks could help by showing me a link or something to this (How to Cluster) including the Virtualmin/Webmin part it would be greatly appreciated. As stated earlier I have had my main server go down twice and i did not find out until after the fact about 3 hours in length. This is unacceptable in my book so I am looking for a way to move them (the sites) from one server to another in case of a failure. Is this possible?

Particulars: Dell SC1435 Quad core servers, 16 gb of ram, 2 - 1.5 TB hard drives, Ubuntu 14.04 Trusty Tahr, 64 bit, 10 GB bandwidth. 2 - 1 gb Nics.

Thank you in advance,

P.S. Still a newbie, in this realm.