Virtual Server overview

Virtual Server overview

Virtual Server 2005 is a server application that enables users to run a range of operating systems—including Microsoft Windows Server™ 2003 and Microsoft Windows® 2000 Server—simultaneously on a single physical server. Virtual Server is designed to run on industry-standard x86-based servers.

A typical server configuration matches hardware with one operating system and the applications designed for that one operating system. The hardware includes the mouse and keyboard, processor, memory, disk drives and drive controllers, video and network cards, and other physical devices. The operating system runs on and controls the hardware. Applications run on the operating system.

By contrast, the virtual machine technologies built into Virtual Server enable one physical server to run an array of operating systems and related applications. A virtual machine uses software and selected hardware devices to create an emulated operating environment.

Virtual machine technology implemented by Virtual Server enables enterprises to run multiple operating systems simultaneously on a single physical server. There are three primary deployment scenarios for Virtual Server:

  • Software development and test automation. The quick creation of new configurations for testing, training, and demonstrations improves developer productivity and test coverage.
  • Application migration. Migrating applications running on obsolete hardware and operating systems onto virtual machines running Windows Server 2003 operating systems on more resilient hardware enables improved application compatibility, manageability, and resource utilization.
  • Departmental and branch office server consolidation. Consolidating servers running line-of-business applications increases application compatibility and manageability, and it also increases resource utilization. Virtual Server allows applications to coexist on the same hardware, thus increasing hardware utilization and manageability while reducing capital costs.

While it is possible to run almost any x86-based application on a virtual machine, some applications are not as well suited as others. When deciding which applications to run on virtual machines, remember that although you can run Virtual Server on a multiprocessor computer, each virtual machine can use a maximum of one processor. This means that enterprise-class applications designed to use multiprocessor hardware may not provide adequate performance if you run them on a virtual machine. When deciding whether to run an application on a virtual machine, consider the virtual machine's physical counterpart. In other words, would you run this application on a physical computer that has one processor?

For example, applications such as Microsoft SQL Server™ or Microsoft Exchange Server will run on a virtual machine. Depending on workload, however, performance may not meet acceptable levels for your organization. It may be appropriate to run these applications in virtual machines for testing or training, but not in a production environment.

For more information about the hardware emulated by Virtual Server, see Emulated hardware. For more information about deployment scenarios, see Virtual Server Usage Scenarios. For more information about features, see Virtual Server features.