Typically, the average computer is idle at least 50% of the time and only performs the task when requested. Even when the computer is working on a task its normally well-under performing its capabilities. The idea behind the virtualisation is to make better use of the computer’s (server) resources. Instead of having one user making minimal use of the resources (CPU power and RAM), you can split the server into smaller computers (Virtual Machines or VM). This will enable multiple users to use the resources and subsequently maximizing the utilisation.
With all servers you would need an OS capable of performing virutalisation, there is a number of virtual applications and platforms which enables this. Each has its on pro’s and con’s. Theoretically, there is no limit to the number of virtual machines one server can create as all the virtual machines are virtual. The only real limit is the capacity of the server’s hard drive in storing the data. Of course there are also the soft limits such as congestion on the server if there is too many virtual machines on the server at one given time and is impacting performance.
As we can see above, we have a dedicated server and we have used virtualisation to create more than one computer, we now have two computers which work side by side consuming the resources of the server simultaneously.
Of course, we can have more than two virtual computers running on the server to maximize utilisation on the server, we can add more and more until we max out the resources of the server. Whether it will be a hard cap due to exceeding HDD space or a soft cap in relation to performance.