Virtual Private Server
A virtual private server (VPS) is a constructive machine sold as a service by an Internet hosting service. A VPS runs its own copy of an OS, and customers have access to that operating system instance, so they can install any software that runs on that OS. For many purposes they are equivalent to a dedicated physical server. They are cheaper than an equivalent physical server, but as they share the elemental physical hardware with other VPSs, performance may be lower, and may depend on the workload of other examples on the same hardware node.
The server virtualization is similar to that which led to the development of time-sharing in the past. Although the resources are still shared, virtualization provides a higher level of security, depending on the type of virtualization used, as the individual virtual servers are mostly isolated from each other and can run their own full-fledged OS which can be independently rebooted as a virtual instance.
Many companies offer virtual dedicated server hosting as an extension for web hosting services. There are many challenges to consider when certification proprietary software in multi-tenant virtual environments.
With unmanaged or self managed hosting, the customer is left to direct his own server instance. However, there are two more kinds of hosting as well; fully managed hosting and semi-managed hosting. In semi-managed, there is a control panel interface for helping users in managing the Linux server while in fully managed hosting, the overall maintenance is offered from server side.
Unmetered hosting is usually offered with no limit on the amount of data-transferred on a fixed bandwidth line. Unlimited hosting is also commonly used but generally limited by terms and conditions. Offers of unlimited disk space and bandwidth are always bogus due to cost, carrier capacities and technological boundaries.
A VPS which is dynamic s often referred to as a cloud server.
Hardware resources can be added dynamically
Server can be moved to other location or hardware while it is running