The number of sites that you host on the server, the number of databases or mailboxes are not limited on a VPS, moreover, Hostens does not block any ports. VPS is a separate server that gives its owner the possibility to customize its settings. On shared hosting, you cannot choose any control panel or any software, as the provider has already configured it. As VPS provides full access (SSH) to VPS hosting, the customer is free to install, manage and control any software that is compatible with server virtualization.
Partitioning a single server to appear as multiple servers has been increasingly common on microcomputers since the launch of VMware ESX Server in 2001. The physical server typically runs a hypervisor which is tasked with creating, releasing, and managing the resources of "guest" operating systems, or virtual machines. These guest operating systems are allocated a share of resources of the physical server, typically in a manner in which the guest is not aware of any other physical resources save for those allocated to it by the hypervisor. As a VPS runs its own copy of its operating system, customers have superuser-level access to that operating system instance, and can install almost any software that runs on the OS; however, due to the number of virtualization clients typically running on a single machine, a VPS generally has limited processor time, RAM, and disk space.