When it comes to hosting, cloud architecture refers to using an individual server for each and every part of the hosting service. Such a setup provides greater performance as one machine will be used just for file storage, a different one only for running databases, and so on, therefore different system processes will not run on the exact same machine. This will decrease the chance of system errors substantially and will allow your sites to run faster, not mentioning the higher uptime. If you are looking for such a service, you have to double check that you'll really find it as a lot of companies advertise cloud internet hosting plans, but the control panels they use aren't designed to function in a genuine cloud and can operate only on a single server. The trouble with using a single machine is that in case one service fails or generates high load, the entire server will possibly go offline, so your sites will no longer be accessible.