Test Center guide: Virtualization for the rest of us

As the virtualization wave washes over datacenter after datacenter, it almost seems that small businesses have been left high and dry. And with licenses for enterprise-grade server virtualization solutions costing tens of thousands of dollars, who could fault a business with only five or six servers for taking a pass?

But nestled among the high-class virtualization tools are plenty of low-cost and even free solutions that fit right in with small-business needs. Tools like VMware Server, VMware ESXi, Microsoft Hyper-V, Citrix XenServer, and open source Xen don't include the high-availability, load balancing, or virtual server migration features needed in large-scale environments. But even without these fancy features, they can make a big difference in the small business's IT budget.

Simply by moving your servers into virtual machines, you make them easy to copy, move, and consolidate on shared hardware. Because all the virtualization solutions support snapshots, you can easily reset a virtual server to a previous version, should you need to roll back undesirable changes such as a malware infection or an update gone wrong. In the event of a hardware failure, you can quickly spin up your virtual server on backup hardware. In other words, virtualization offers small shops the same sorts of benefits it offers large data centers, even if automation isn't part of the bargain.

[ See the Test Center reviews of Microsoft Windows Server 2008, Hyper-V and System Center Virtual Machine Manager, VMware Infrastructure 3 with ESX Server 3.5 and VirtualCenter 2.5, and Citrix XenServer and XenDesktop. ]

A six-server scenario
To illustrate the impact that free virtualization tools can have on a small business, let's take a typical small-business network. There might be six servers, including a couple of domain controllers that also run DNS and DHCP services, perhaps a Microsoft Exchange server, a Web server, a database server, and a file server. These systems might be running on any mix of hardware, with the most active services using the newest, fastest boxes, while the domain controllers and the file server might get by on older equipment. For an office of, say, 50 people, this infrastructure is common.

However, looking at the utilization of those servers, it's highly likely that none of those servers is running above 15 percent capacity. That is, they're barely using the CPU and memory resources they have. Clearly you've got a whole lot more hardware than you really need.

And resource utilization doesn't paint the whole picture. For instance, the domain controllers might be running on dual-CPU servers with 4GB of RAM, when even half that would be overkill. Likewise, the Web server could be wasting a perfectly good dual-core processor if it's only serving a few Web-based applications and an intranet page or two.

An infrastructure like this, in which plentiful hardware resources are required but underused, is ripe for virtualization. The first step toward this goal is to evaluate the options. For this network, they're probably limited to four: Microsoft's Hyper-V, VMware Server, VMware ESXi, and Xen.