It's the recognition that virtualization technology presents administrators with particular management challenges in addition to those associated with conventional server management that has driven the development of Microsoft's Virtual Machine Manager 2007, part of the System Center family of management products.

The attractions of server virtualization are very clear. Virtualization enables organizations to reduce the number of physical servers they need, while increasing the utilization rate of those that remain from a typical value of 5 to 10 percent to 60 percent or more. The introduction of virtualization technology can also lead to a significant reduction in energy consumption, as there are fewer physical servers to power, and less cooling is required to dissipate the heat these servers generate. Energy consumption is rapidly becoming a far from trivial issue: research house Gartner estimates that as much as 5 percent of many corporate IT budgets is consumed by energy costs, and when predicted energy price increases are factored in, this figure could rise as much as 15 percent in the next five years. An energy-inefficient data center also reflects poorly on the organization concerned, especially if, as is increasingly the case, it has published corporate social responsibility commitments.

Perhaps the biggest advantage that virtualization offers is business agility. While physical servers can take weeks or even months to provision, virtual servers can be made available to users that require them in a matter of hours, either by IT department personnel, or through self-service provisioning systems. The increase in productivity that stems from having systems available when they are needed can be very significant indeed.

In order to realize these benefits, there are a number of infrastructure management problems that first need to be overcome. How does an organization virtualize its servers without disrupting operations, and what's the most efficient way of allocating these newly created virtual machines to the physical servers that are to host them? How does it ensure that new virtual machines are provisioned with the correct configurations for their intended uses, and what's the best way to keep track of them and monitor their health? And how does it prevent "virtual machine sprawl" by ensuring that virtual machines that are no longer required are removed from their host servers and either deleted or stored for later reuse so they do not use up computing resources unnecessarily?

Microsoft's comprehensive approach to virtual machine management is to add the extra capabilities that a virtualized environment requires to System Center through its Virtual Machine Manager product, so that organizations can manage their physical and virtual servers simultaneously with the same System Center tools.

This means that in a mixed physical and virtual server environment managed by System Center, Virtual Machine Manager provides features for provisioning and other virtual machine specific tasks, while Operations Manger, for example, provides the unified health monitoring and Data Protection Manager provides the continuous data protection for all the servers -- both physical and virtual.

Many administrators will choose to use the Virtual Machine Manager administration console, which is built on the System Center Operations Manager 2007 interface, to manage environments that can include hundreds of virtual machines. This administration console includes search, sorting, categorization and navigation features, and is integrated with Operations Manager 2007 so that the underlying physical environment of any group of virtual machines can be understood and managed at the same time. But since the Administration Console is built on top of Microsoft's PowerShell command line interface, those who prefer a more direct approach can also carry out any action performed in the graphical environment from the PowerShell command line.

Administrator-authorized end users -- those working in a development and test environment, for example – can also provision their own virtual machines on a "self-service" basis subject to controls set by the administrator, using the Web-based Delegated Management and Provisioning portal.

A key feature of Virtual Machine Manager is its ability to manage the entire process of server virtualization. It starts this process by analyzing historical performance data stored in the Microsoft Systems Center Operations Manager database to identify servers suitable for virtualization. Virtual Machine Manager then takes care of the actual process of converting servers from physical to virtual machines (known as P2V conversion) with a wizard-based process using Windows Server 2003 Volume Shadow Copy Service so servers can be virtualized "on the fly", without the disruption of having to take them out of service first.

The final part of the process is the allocation of newly created virtual machines to physical host servers. This is a surprisingly hard task to carry out efficiently, as the processor and memory requirements of each of the virtual machines have to be paired with a server with the appropriate resources available so that peak usage patterns of both the virtual machine and the underlying physical server can be accommodated. Virtual Machine Manager carries this out using a feature based on modeling technology from Microsoft Research called Intelligent Placement, which takes data from the available physical hosts and any historic data from Systems Center Operations Manager to identify the most suitable host for a particular virtual machine.

Another key feature of Virtual Machine Manager is its ability to control the lifecycle of virtual machines to prevent them being created unnecessarily, to make it easy to remove machines from service and place them in storage, and to act as a library holding templates for virtual machines which have been predefined for particular applications, departments or users, and for virtual hard disks, CD/DVD software images, and post-deployment configuration scripts. For organizations with branch offices, these library servers can be distributed around the network to enable the rapid creation and deployment of virtual machines at remote sites.

With the introduction of Virtual Machine Manager 2007, Microsoft's System Center offers a complete infrastructure management solution, which enables organizations to manage their virtual and physical computing assets using a common set of management tools. This makes administration highly efficient, and helps ensure that maximum benefit can be derived from a virtualized server environment.