Server virtualization helps in cost reduction by utilization of single hardware server to multiple virtual servers (VMs). It improves efficiencies highly by separating different functions/services. VMs also improves security and data availability. Server virtualization can also be multi-Operating systems Windows/Linux/Unix etc. with different functions like File Server/Exchange Server/Security Server etc. This gives you the flexibility and eliminates the need of purchasing separate hardware for each. In this way it reduces the service, management, monitoring and support costs.