Why Virtualize SharePoint?
Virtualizing SharePoint and its server components can provide many business and technical benefits. With virtualization, you can consolidate hardware and ease server management and provisioning—helping to promote cost savings, business continuity, and agile management. Moreover, SharePoint virtualization is ideal for organizations that have more than one SharePoint farm, such as those with high availability production, testing, and development environments. The remainder of this section describes additional benefits of SharePoint virtualization in greater detail.
Hardware consolidation essentially allows you to run different SharePoint servers and various server components sharing the same hardware set. Hardware consolidation yields a variety of benefits:
Resource utilization and balancing: With SharePoint virtualization and the built-in enhancements of the Hyper-V 64-bit multiprocessor and multicore technology, you can run multiple workloads on different, isolated virtual machines—helping to use and balance resources more efficiently. Because you manage only a single physical server that runs isolated virtual machines, it is easier to provision and balance various resources, such as RAM and disk space, for different SharePoint server components.
Reduced costs for physical infrastructure, maintenance, power, and cooling: Server consolidation reduces server count, which, in turn, reduces the cost of SharePoint infrastructure and maintenance. Consequently, cooling needs and power consumption are also reduced. From the perspective of environmental sustainability, SharePoint virtualization can be a major contributor to the Green IT movement.
Less physical space: By virtualizing SharePoint farms, you can provide required capabilities with fewer servers, thereby freeing up space originally allotted for servers.
SharePoint 2010 virtual Architectures for Small-to-Medium Farms
SharePoint 2010 Virtual Architectures for Medium-to-Large Farms
Source: SharePoint 2010 Virtualization Guidance