Virtual Machine Technology FAQ

Virtual machine technology enables multiple operating systems to run on a single computer at the same time. It applies to both server and client hardware. Microsoft Virtual PC and Microsoft Virtual Server 2005 enable one or more x86-based operating systems to run on the same computer system. Virtual PC for Mac enables one or more other operating systems to run on the Macintosh operating system so that users can run a Microsoft Windows operating system and a Windows-based application on a Macintosh computer.

Virtual machine technology serves a variety of purposes. It enables hardware consolidation, simplified system recovery, and re-hosting of earlier applications because multiple operating systems can run on one computer. One key application for virtual machine technology is cross-platform integration. Other key applications include the following:

Virtual Server 2005 is the most cost-effective virtualization technology engineered for the Windows Server System. As a key part of any server consolidation strategy, Virtual Server increases hardware utilization and enables organizations to rapidly configure and deploy new servers. The current release is Virtual Server 2005 R2, which has key features that support virtual machine high availability, x64 hosting support, and increased performance.

Microsoft Virtual PC 2004 is a virtual machine solution for desktop operating systems. Microsoft Virtual Server 2005 is a solution for server operating systems. Although Virtual PC and Virtual Server have many features in common, they are designed for different purposes and some of their features are also very different. For an explanation of the differences between Virtual PC and Virtual Server and a discussion of the various scenarios that apply to one or the other, download the Virtualization Whitepaper from the Volume Licensing Briefs Downloads page.

For information about licensing in a virtual machine environment, download the licensing brief Licensing Microsoft Windows Server and Other Microsoft Server Software for Microsoft Virtual Server 2005 or Other Virtual Machine Environment (Microsoft Word file, 307 KB).

You may not transfer OEM server licenses from the original machine to a different machine. Any Microsoft Windows Server license that is preinstalled on a new computer from an OEM or that you acquire through any Microsoft Volume Licensing program is tied to the computer on which the licensed software is first installed. This applies to the initial copy that is installed on the computer and to any subsequent copies that are licensed to run with virtual machine software.

However, if you have enrolled this license in the Microsoft Volume License agreement and purchased Software Assurance for this preinstalled license within 90 days of the original purchase, you receive the benefits, including license reassignment, associated with the Volume License program. You can then move that license from one computer to another, including to a virtual machine.

Each installed copy of a Windows server operating system must be licensed separately. For example, if you are setting up four virtual machines within Virtual Server 2005 to run one instance of Microsoft Windows 2000 Server and three instances of Microsoft Windows NT Server 4.0 at the same time, you will need one Windows 2000 Server license and three Windows NT Server 4.0 licenses. These licenses are in addition to the Microsoft Windows Server 2003 host license running Virtual Server 2005. You must have or acquire Windows Server licenses for the maximum number of copies of the software that will be installed or run.

With the Microsoft Windows Server 2003 operating system, Enterprise Edition, you receive use rights for four virtual machines under one physical license. In this case, if you are setting up four virtual machines within Virtual Server 2005 to run one instance of Windows 2000 Server and three instance of Windows NT Server 4.0 at the same time, you will need to purchase only one Windows Server 2003, Enterprise Edition license as the host.

A Windows Server 2003 CAL is required for each user or device that accesses the virtual machine while it is running on the host operating system (Windows Server 2003).

No. You may benefit from moving the applications from physical hardware to virtual machines. However, running applications in a virtual environment does not extend their support life cycles. For more information about the support life-cycle timeframes, go to the Microsoft Support Lifecycle page.

The number of virtual machines that can run per host depends on several things, including physical memory, processor, and workload running in the guest. With Virtual Server 2005, you define the amount of memory available to a virtual machine. That memory allocation can be altered to reflect the needs of the virtual machine. For more information, read the Virtual Server 2005 Technical Overview White Paper.

Yes. You can download the tool from the Microsoft Virtual Server 2005 Migration Toolkit page.

Virtual Hard Disks (VHD) can be stored on a SAN. A host operating system views a SAN volume as a local volume. Therefore, no special configuration is needed when you use Virtual Server 2005 with a SAN. For more information, search for "SAN" in the Virtual Server Administrator's Guide. Virtual Server 2005 R2 now can cluster the Virtual Server hosts based on shared storage, which includes SAN architectures.

Licensing does not depend on which virtualization technology is used. With a license for Windows Server 2003 R2, Enterprise Edition, you can run one instance of the software in a physical operating system environment and up to four instances in virtual operating system environments. With VMWare GSX Server, this means you can run one physical instance plus four virtual instances. With VMWare ESX Server, it means you can run four virtual instances because there is no need for a physical instance.

If the organization has Software Assurance, it can upgrade its licenses for Windows Server 2003, Enterprise Edition, to licenses for Windows Server 2003 R2, Enterprise Edition. If it has Software Assurance, it can purchase step-ups from Windows Server 2003, Standard Edition, to Windows Server 2003, Enterprise Edition (and then upgrade those to Windows Server 2003 R2, Enterprise Edition). Volume Licenses can be reassigned every 90 days from one physical server to another. OEM licenses cannot be reassigned.

An inactive virtual machine does not need a separate license for any Microsoft server products. If an organization creates a virtual machine and the virtual machine is not running, then the organization does not need a separate license for the software in that virtual machine. With the "license by running instance" enhancement, one license allows the organization to create any number of instances or backups of the software. For example, if the organization has one license for Windows Server, then it can create any number of instances or backup copies of Windows Server.

SQL Server specifically has the "passive failover" exception; an organization can actually run a second instance of SQL Server. However, that instance must be passive, not active. The organization can run that instance in a virtual machine on the same server or in a virtual machine on another server. For example, if the organization has a virtual machine running SQL Server on Server A, it can create a passive instance of SQL Server in a virtual machine on Server B. Both the virtual machine on Server A and the one on Server B are running. However, the instance of SQL Server on Server B must be passive. ("Passive" in terms of "passive failover" means an actual running instance that is not doing work.)