The most critical factor for enterprises opting for server virtualization is the cost benefit in terms of hardware and power consumption.

However, a recent global survey carried out by Canada-based Strategic Counsel on behalf of CA revealed that 28 percent of organizations which deployed server virtualization either failed to realize a return on investment (RoI) or are unsure whether they realized RoI. Another 40 percent either failed to realize documented cost savings or were unsure of the cost savings they achieved.

“An ideal server virtualization implementation is when an organization standardizes on one virtual machine (VM) software vendor and leverages the vendor’s system management suite to manage all VMs across all physical hosts,” says Matt Brudzynski, Senior Research Analyst with Info-Tech Research Group, also based out of Canada. He adds that the key to success lies in having a homogenous virtual server software environment that is integrated across the enterprise.

The survey further cites issues and constraints responsible for negatively influencing server virtualization satisfaction levels. These include server sprawl (a situation where multiple, under-utilized servers take up more space and consume more resources), increased configuration and administration requirements, and difficulty with reporting, visibility and metrics for obtaining one constant view on server efficiency, performance and utilization.

“Provisioning of servers at the OS level is a challenge and hence the above-mentioned issues. Enterprises should carry out provisioning at a higher level like the application platform layers of J2EE and .NET where the applications actually run,” says Ramesh Loganathan, VP for Middleware at the Hyderabad-based Pramati Technologies.

Another area of concern is the security issues associated with server virtualization. According to Gartner, if server virtualization is carried out without implementing best practices for security, it may increase costs and reduce agility. A report from the research major states that through 2009, 60 percent of production VMs will be less secure than their physical counterparts.

“To ensure security, enterprises will spend on software management and administration of virtualized server environments,” says Naveen Mishra, Senior Research Analyst, Gartner.

Gartner opines that the process of securing VMs must start before they are deployed, and ideally, before vendors and products are selected. This will equip enterprises to factor security issues during the evaluation and selection process.

Info-Tech Research, in its report on server virtualization, states that vendors tend to exaggerate the number of servers that can actually be consolidated. This can be misleading for enterprises looking to invest in this technology. “We discovered that as additional VMs were added, an input / output bottleneck (communication bandwidth with the SAN / NAS) appeared and degraded performance on the virtual hosts. The number of VMs had to be scaled back,” informs Brudzynski.

The high consolidation rates claimed by vendors is not happening because customers need to leave adequate capacity on existing host servers for load-balancing, emergency back-up and ensuring adequate data throughput to disk storage.

Brudzynski asserts that the only issue which requires immediate attention is server sprawl. “Server sprawl with VMs would create a larger problem because of the speed with which the servers can be spawned,” he explains.