"We have [guest] server templates and put a lot of effort getting it right since every server is a little but different," Maftoum said. "We went from about 15 virtual machines to 88, including a lot of P2V migrations."

ACMA has been able to shut down more than a 20 physical servers and Windows 2008 R2 is the standard guest operating system. Maftoum said the Linux-based XenServer hypervisor performs "extremely well", hosting Windows server quests with between 15 and 20 virtual machines per physical host.

"There are no issues with the load on the machines and we will add more machines to expand our virtual infrastructure," he said. "The management tools are good. We have found them extensive and useful. A lot of the ESX project work like templates was brought over to XenServer. ACMA works closely with Microsoft at different levels and Maftoum said it received strong support for running on XenServer.

"Xen has a level of maturity in the Linux space. Citrix is adding support around it and that is a good strategy. I can't speak highly enough of it."

Maftoum said the cost saving between ESX and XenServer was "substantial" at about half the price.