Cassatt's Collage is a grid management system that manages a group of servers as a pooled resource. It can adhere to service-level agreements or other built-in performance rules to provision more servers of the type needed as traffic on the grid mounts. With the debut of its Web Automation Module earlier this month, Collage is able to separate its management of WebLogic application servers from the hardware on which they run and treat them as a pooled resource as well. Load-balancing software on clusters operates in a similar manner, but Cassatt has moved virtualization a step ahead of load balancing, Illuminata's Eunice says. The Web Automation Module "is smart about middleware," he says. "Instead of viewing it as baked in with the operating system and application, it thinks of it independently."

Ties That Don't Bind

The advantage of treating middleware independently from the hardware and applications is greater operational flexibility and more dynamic allocation of resources, Lynn says. A WebLogic application server tied to one or two applications can't be reallocated to serve other applications, even when those apps are experiencing low traffic--unless the tie between app server and a particular application can be superceded, as Cassatt's software does.

WebSphere Extended Deployment can virtualize application server resources by creating many small virtual machines in logical partitions on IBM servers, allocating more Java virtual machines and WebSphere application server units as demand increases, an IBM spokesman says. Such an approach can be made to work much like Levanta's or Cassatt's, Eunice says, but more administrative configuration and intervention are required.

"In the past, we've not been all that sophisticated about separating the middleware from the operating system layer," Eunice says. The operating system, application, and middleware each exist in many different versions and stages of patching. Combining them in a virtual machine sounds simple, but many variations of the combination ensue and "it gets really messy out there," Eunice says.

Using the Cassatt software over a three-year period, Pfizer will save "several million dollars" in reduced costs, thanks to the virtualized server grid, Lynn says. (A posting on Cassatt's Web site touts Pfizer's projected savings at $5 million, but Lynn says that figure was based on preliminary modeling.)

The savings stem in part from higher server usage levels. For example, WebLogic servers will go from about 40% utilization to 75% and higher, Lynn says. Some hardware servers will go from less than 10% utilization to 50% as multiple virtual machines are stacked up on what used to be siloed servers running single applications. Beyond savings from buying less hardware, often fewer software licenses need to be purchased as well.

But Illuminata's Eunice says the real savings that spring from extensive virtualization of the data center come from the ability to manage those servers with fewer people. "Virtualization is a huge enabler by taking the people cost out of the equation."