Virtualization improves efficiency, but brings power and cooling challenges

Virtualization is making data centers more flexible and efficient, but the technology is also raising new challenges, IT managers say.

Consolidating onto fewer physical servers is one of the technology's key benefits, but John Turner of Brandeis University in Massachusetts notes that the cooling needs of a virtualized server are quite different than the needs of a server running only one application.

With virtualization increasing CPU utilization to 70%, "that generates a lot more heat," says Turner, director of networks and systems at Brandeis. "If you walk behind the racks of virtualized servers, the heat is just pouring out of those guys. … We're seeing heat dump into these rooms like never before."

Turner and many other speakers will share their expertise in Boston Wednesday at Network World's IT Roadmap Conference & Expo, a one-day event occurring in 10 cities this year.

Using VMware and Xen, Brandeis has virtualized nearly all of its servers over the last couple of years, reducing its total number of physical servers from about 120 to less than 30 today. But Turner says his power use has increased on the whole because virtualization has made it easy to spin up many new applications that he didn't run when Brandeis used only physical resources.

Also contributing to the power crunch is Brandeis's use of a high-performance computing cluster and Moore's law of increasing processor speeds. Brandeis has managed growing power needs by increasing the size of uninterruptable power supplies, says Turner, who specified using APC's Symmetra for its scalability.

"We're having to adapt the data center [which was built in the 1960s] to new demands that in the past just weren't there," Turner says.

Ultimately, the goal is to examine usage over time and power down unused nodes, while more intelligently managing live migration capabilities, he says.

IT Roadmap will also feature keynote speaker Madge Meyer, executive vice president of global infrastructure services at State Street, which is virtualizing on a completely different scale, having applied the technology to about half of the company's 10,000 servers worldwide.

Virtualization has improved State Street's development environment and made the provisioning of new servers simpler and faster, but Meyer says not every workload is appropriate for the technology.

"Applications that require a lot of processing power are not good candidates for virtualization," Meyer says.

Storage-area network technology is also just starting to catch up with the realities of virtualization, with the number of required storage volumes growing as IT packs more virtual machines onto fewer physical boxes, Turner says.

But virtualization will be essential at State Street as it considers building a private cloud network. While the details and implementation date have not been figured out, Meyer says her team is hoping to harness virtualization, Web services and other technologies to build a network that lets users request new services and get them quickly, without having to worry about buying a server or setting up storage.