In the phrase ” VPS Hosting ,” VPS stands for Virtual Private Server — it is a term Internet hosting services use when referring to an independent virtual machine that is used exclusively by one customer. A Virtual Machine is defined as a system installation that is totally isolated from an overlaid operating system that runs the hardware as one function among many. The implementation of a Virtual Machine can be done via either a software emulation or a hardware virtualization. Whichever method is used, VPS Hosting benefits both the hosting service, who can be more efficient, and the customer, always on the look-out for the best VPS hosting solution.

A virtual machine for one customer runs within a single physical computer that contains the virtual machines of many other customers. Yet, that single virtual machine acts as though it is a single physical computer that is reserved for the needs of the individual customer. Managed VPS guarantees that each VPS has the same privacy as though it were a single physical machine. And, of course, the VPS can be set up to run as a server — hence, the name VPS is proper and correct. The acronym VDS, for Virtual Dedicated Server, is a less common name for VPS Hosting .

Because a virtual server is able to act as its own operating system without being controlled by the VPS host server operating system that is used to run the managed VPS as a whole, a customer can run a VPS as their own machine for whatever purpose is needed — its own virtual operating system can be rebooted as required. The concept of setting up individual partitions on a single physical server to contain multiple virtual servers has been around for decades in the world of mainframe and middle-range computers. Virtualization has become more common with the invention of similar hardware technologies for micro-computers and workstations and the development of the related virtualization software.

In the best VPS hosting solutions, the main physical server runs what is called a hypervisor — it keeps track of the virtual machines housed within itself as separate virtual operating systems. The hypervisor acting as the VPS host invisibly allocates computing resources to each guest VPS — each virtual machine is not aware of the actions of the hypervisor, but each does recognize the allocated resources and treats them as its own.

In a managed VPS , all of the guest systems can be fully virtualized or partially virtualized

When a VPS host environment is fully virtualized, each guest system perceives the hardware resources allocated by the hypervisor as its own and only its own — the guest system is not aware that the hardware it preceives is not actually its own. One drawback of a fully virtualized VPS host is that the hypervisor must use a significant amount of available resources for its own purposes in translating all resource requests from guest VPS systems into mappings and actual resource requests that will interact with the physical hardware resources. No operating system modifications are needed to set up this type of VPS hosting , but the physical server must have a CPU that supports visualization so that the software hypervisor can manage the best VPS hosting possible from that hardware.

When a VPS host environment is partially virtualized, the hypervisor handles only access control and allocation of hardware resources. Each guest VPS not only interacts directly with the actual hardware resources, but also works with the hypervisor in handling the VPS interface. Less overhead is used by the hypervisor than in fully virtualized VPS systems because the guest systems take on part of the load of interacting with the hardware. Many UNIX and UNIX-like OSs, including OpenSolaris and BSD, support this type of virtualization. But, any guest systems in partially virtualized environments must be more knowledgeable about how the operating system interacts with the hardware and must have special drivers and kernels that are hypervisor-aware.

Hybrids of fully virtualized and of partially virtualized environments also exist for those OSs that cannot be modified for virtualization support. In this type of hosting environment, a guest system uses para-virtualized drivers for Disk I/O and Networking services in order to increase the I/O performance in a managed VPS solution.

VPS hosting environments are the bridge between shared hosting services, which uses only one OS on one physical server for many guests, and dedicated hosting solutions, which provides the total resources of a single physical server to each customer. Under standard practices for most VPS hosting companies, each participating customer will be able to install their own software within their own OS as they please. Certain software, however, does not work well within a virtual environment — for example, a software virtualizer does not work within a virtual OS for obvious reasons.
Customers must choose the best VPS hosting option for their specific needs.