By investing in virtualisation software, a small US college eliminated about one-third of its physical servers and sidestepped about £190,000 for new systems, even as it added enterprise applications.

The server consolidation at Bowdoin College in Brunswick, Maine, grew out of a limited test of ESX Server, virtualisation software from EMC subsidiary VMware. Initially, the IT group wanted to use the software to create virtual servers that could be dedicated to testing new or upgraded applications before they were deployed in full production mode.

Two years ago the IT group launched a trial deployment. The ESX software is in charge of the physical computing resources -- CPU cycles, memory, disk space -- and allocates these in response to application demands. The applications run in virtual machines, self-contained software bubbles with a claim to the underlying CPU resources on the blade.

"It's kind of like the old mainframe model, where each user's job got a slice of the CPU's time," says Tim Antonowicz, Bowdoin's systems administrator. "VMware ESX Server does the same thing with the virtual machines: It drops a VM onto the blade server hardware, runs the cycles it needs and then [drops on] the next one, cycling through all of them." The virtual machines are exploiting what previously would have been idle CPU cycles. As Bowdoin discovered, applications now can run on fewer physical servers. Virtual machines can be created within minutes or allocated additional virtual memory or disk space with a few mouse clicks. A new application can be safely tested, or an old one modified, on one or more dedicated virtual machines and then deployed quickly.

These virtualisation virtues became apparent in late 2004, as Bowdoin's infrastructure was stretched to the limit. The small data centre was jammed with five racks of servers, and many of them sat idle for most of the day. At the same time, Mitchell Davis, the college's first CIO, was planning to rewire the campus for Gigabit Ethernet and to deploy application upgrades to serve about 1,600 students, 179 faculty and 600 staff.

The new financial system, Blackbaud's Financial Edge, would need 10 to 16 new servers to support the configuration.

"The IT staff came to me and said, 'We think we can deploy everything on VMware,' " Davis recalls. Bowdoin bought 15 HP BL20 blade servers. Eight blades run ESX Server instances, with a ninth instance running on a Dell server. The IT staff was able to reduce the number of physical servers from 72 to 46 (including the 15 HP blades).

Today, Davis says 58 per cent of Bowdoin's applications run on virtualised servers. The 15 HP blade servers cost $93,000 (about £49,400). VMware's ESX pricing for the education market is $3,000 (about £1,600) per server, which can each support multiple virtual machines, for a total of $27,000 (about £14,350).

Antonowicz says that to support the new applications deployed, 57 additional physical servers would have been needed. But as a result of using virtualised servers, Bowdoin bought none apart from the blades. Antonowicz estimates the 57 boxes would have cost $356,250 (about £190,000).

Monitoring and managing the new server environment has been dramatically streamlined. "I can add memory, increase a hard drive, add a second CPU or network card, all from a secure VMware Web interface," Antonowicz says.