Hyper-V makes it possible to consolidate servers onto a much smaller number of physical machines, significantly reducing power consumption without unduly sacrificing performance. Multiple virtual machines can run on a single physical machine without consuming significantly more power than a standalone server while keeping comparable throughput. This means you can add virtual machines at essentially no power cost, as dictated by your hardware and performance needs. The savings continue to scale with the number of servers you are able to virtualize. Running 4 virtual machines means saving the equivalent power output of three physical servers; running 10 virtual machines means saving the equivalent power output of 9 physical servers.
The Windows Server 2008 Power Savings White Paper details some of the savings:
- A single Hyper-V server with 10 virtual IIS servers can reduce your CO2 output by more than 30 metric tons compared to the output of 10 physical servers with the same hardware profile. In carbon terms, this is the equivalent of burning 1,500 liters of gasoline, rather than 14,000 liters (or 396 gallons rather than 3,698 gallons).
- At the current market rate of about €25 per metric ton for European carbon allowances, even this modest Hyper-V deployment could free up carbon credits worth €750, or more than $1,100 USD, every year.
- Power usage of a single Hyper-V server hosting 4 or 10 virtual machines did not differ significantly from the power usage of the same server when hosting a single instance of IIS7, all while maintaining comparable performance. With 4 virtual machines on a single host, the power usage per server is effectively one fourth, and with 10 it is effectively one tenth.
Read more about Energy Efficiency Best Practices in Microsoft Data Center Operations on the Microsoft Environment site.