A virtual machine is a great tool for testing server implementations, web applications, and new operating system versions. It is also great for development environments and can even be used on mobile computers to make work easier. Nevertheless, there are also situations where you might benefit from long-term or permanent virtualization.
The essential premise of a virtual machine is that it enables you to run an operating system within an operating system, while giving both direct access to the hardware. Although this often means running one operating system within another, you can also run multiple instances of the same OS on a single dedicated server. What follows are a few scenarios for long-term virtualization:
1. VPS. Virtual Private Servers are basically virtual machines that give the users all of the functionality and privileges of a full server. Each virtual machine is housed within a container that the server administrator controls.
2. Maximizing server usage. In some cases, it may be more cost effective to run Windows and Linux, for example, on the same server rather than buying two separate machines, especially if neither virtual server will occupy all of the system’s resources.
3. Cluster virtualization. A server cluster need not all be dedicated to a single operating system with a single task. Virtualizing a cluster may be ideal in situations where the administrator wants control over every machine as a single entity but also wants the flexibility of several different configurations.
Virtualization has many benefits beyond those mentioned above, and there are numerous virtualization solutions for Linux, Windows, FreeBSD, Solaris, and nearly every other operating system. Notable virtualization software solutions are Xen, KVM, VMWare, and Microsoft Hyper-V Server.