Virtualization costs do not stop with hardware, software and other tangible items. There are lots of other hidden virtualization costs and, often, many of them are not recognized until the project is already underway. They include the costs of network and storage hardware upgrades, security and training.
Cost of network hardware upgrades
Server virtualization and consolidation projects should also be considered for network and storage implications, which are two crucial elements of the IT infrastructure frequently overlooked when you calculate return on investment (ROI) or total cost of ownership (TCO).
Moving multiple virtual machines (VMs) onto a single physical server may demand additional NIC and switch ports to support added bandwidth needs. High-end consolidation projects may even justify a 10 Gigabit Ethernet segment, but then you must add the corresponding NICs, switch ports, cabling and deployment labor -- all of which will add to your total virtualization costs.
Cost of storage software and hardware upgrades
Server consolidation projects can overwhelm access to the storage network, said Eric Perkins, chief technology officer at Cyberklix, a security and networking tool provider in Chicago.
"Not enough consideration is given to storage, the network connectivity to storage, and to your virtual machines' redundancy in network connections," he said. "When you're centralizing so heavily, those network connections to storage are your lifeblood."
The planning and testing phase of any server consolidation project should examine storage requirements and assess performance. Major consolidation efforts may justify SAN performance improvements, which will add more virtualization costs to your project. Added storage capacity might also be needed, but management tactics, like thin provisioning, can accommodate more logical unit numbers while deferring the storage capacity until the space is actually needed.
Cost of security
Although it's common practice to deploy security products on individual servers, applying security between VMs is still in its infancy. Each organization must weigh the need for VM security and deploy the appropriate products to meet security-centric compliance regulations where they're appropriate.
"You should have host-intrusion prevention on your VMs," Perkins said, adding that inter-VM security vulnerabilities are still fairly rare but can be prevented with host intrusion and software firewall products.
Cost of training
Supporting a virtual server infrastructure is different than supporting a bare-iron data center. It requires a slightly different set of administrative and management skills. Training staff to develop these skills adds to your virtualization costs.
Management tools make it easy to create and delete VMs in bulk. This might require fewer personnel, but it absolutely demands a superior knowledge of the toolset along with a clear understanding of the business workflow requirements for VM management.
"You need to look at these virtual instances differently than you would a physical instance," Perkins said. "It still needs lifecycle management though."
Cost of downtime or disruption
Reliability is acutely important in a virtual environment. A fault in one physical server can disrupt numerous VMs along with all of their users. Planning is required to minimize the downtime when migrating from a bare-iron server to a virtualized server and to ensure adequate redundancy or failover once you've implemented virtualization.
Productivity lost because of downtime or poor performance is one of the intangible virtualization costs that's difficult to nail down, but it can adversely affect ROI through spending for corrective action. For example, improper workload balancing can impair the performance of all VMs on the physical machine. There is, however, an upside in workload flexibility. The ability to move workloads without disruption off of a server that is failing and then repair that server immediately during normal work hours is a valuable benefit.
Cost of workflow changes
Server virtualization will change the way that server resources are created and assigned in the enterprise. For instance, consider how server virtualization will change backup and disaster recovery (DR) and business continuity (BC) plans.
"DR plan updates and testing rate very high on the list, mostly because organizations collectively don't update DR/BC plans as regularly as they should," said Allen Zuk, president and CEO of Sierra Management Consulting LLC, an independent technology consulting firm based in Parsippany, N.J.
Keep in mind that the cost of workflow changes can ultimately save money for the company.
Cost of management
Ideally, when it comes to management, virtualization costs should decrease -- mostly because of the automation provided by VM management tools. But be sure to implement automated management with attention to workflow changes that define VM lifecycles and control VM sprawl.
"I think the management costs could actually increase if you're not careful," said Gary Chen, research manager for enterprise virtualization software at IDC. "If you don't really have good processes for provisioning and de-provisioning and for keeping track of VMs, you can definitely eat up a lot of the savings. You could wind up spending a lot more."
About the author
Stephen J. Bigelow, a senior technology writer at TechTarget, has more than 15 years of technical writing experience in the technology industry. He has written hundreds of articles and more than 15 feature books on computer troubleshooting, including Bigelow's PC Hardware Desk Reference and Bigelow's PC Hardware Annoyances. Contact him at firstname.lastname@example.org.