Virtual web hosting is a type of web server hosting in which the servers are entirely virtual, i.e. emulated by software. The server on which the emulation software runs – typically much more powerful than the virtual server – is referred to as the "real" or "metal" server.
This arrangement allows software control over many things, including the specifications of the virtual server (CPU, RAM, disk size), without any physical intervention. A virtual server also does not depend on any particular piece of hardware, and can be quickly moved to different hardware in the event of hardware failure or maintenance.