Expand Virtual Machines Carefully

The pervasiveness and influence of virtualization in the enterprise is astounding. Virtualization has changed the way IT views, deploys and manages the infrastructure. Mature server virtualization environments are boasting reduced downtime, simplified disaster recovery and faster deployments. However, the rate at which these virtual machines are deployed has lead to virtual machine sprawl.

Nearly 60 percent of CIOs and other executives around the world consider virtual server management a high IT priority, according to Systems Management News.

"Over the last three years, the virtualization phenomenon has been rapidly transforming the x86 landscape," said IDC analyst Tim Grieser. "In many cases it has boosted server utilization rates from below 10 percent to around 60 percent."

Grieser, program vice president for the Enterprise System Management Software group at International Data Corp. of Framingham, MA, provided an informative rundown on the growth of virtualization in the enterprise, and how it relates to the fields of capacity planning and performance management at the TeamQuest Technology Summit.

He laid out the evolution of virtualization, harking back to the mainframe days. The technology, for example, has a long history on zSeries mainframes, as well as high-end UNIX. These are now mature virtualization platforms, of course. Virtualized x86 servers, on the other hand, cannot be characterized as anything more than emerging. But with 10 percent of new server shipments now including virtualization software and about 5 percent of the entire Intel server landscape utilizing virtual machines, virtualization is being forced to grow up rapidly.

In terms of advantages, virtualization has brought higher utilization, server consolidation, workload flexibility, less downtime and reduced time to provision. But Grieser stressed the many challenges that virtualization brings.

For example, a little understood fact is that virtual machines exert a higher performance overhead compared to physical servers - though IDC expects this to diminish over time. In addition, some workloads don't run well in such an environment, and network traffic can degrade under virtualization.

Perhaps the biggest problem, though, is unchecked virtual machine expansion. Companies are slowly waking up to the fact that physical server sprawl is being replaced by its virtual equivalent.

"Proliferation of virtual machines starts immediately and rapidly becomes virtual machine sprawl," said Grieser. "Thus many companies are growing concerned about how to manage a virtual infrastructure."

Capacity management, he said, plays a vital role in remedying this situation. IDC defines the term in alignment with ITIL v3. As such, it provides a point of focus and management for all capacity and performance related issues, relating to both services and resources, and matches the capacity of IT to the agreed business demands.

The beauty of capacity management, Grieser says, is that it allows you to do what-if analysis for use-case scenarios, determine the impact of changes on system performance and build mathematical models to calculate the impact of changes. Finally, it is invaluable in supporting ongoing sizing and provisioning initiatives.

"Capacity planning tools such as TeamQuest play an important role in cost containment within a virtualized environment, as well as demonstrating ROI," said Grieser. "TeamQuest enables you to look at the physical server and also drill down into the individual virtual machine to see graphically how it is performing."