Your How-To Guide To Server Virtualization

Now you’re ready to arrive at a target “consolidation ratio” indicating how many virtual machines your customer can safely place on each of the company’s physical hosts. Avoid basing that figure solely on recommendations from hypervisor makers, says John Sloan, a senior research analyst at Info-Tech. A rigorous capacity planning assessment will provide more reliable guidelines. Such studies calculate total server resource requirements across your client’s entire infrastructure. Numerous vendors, including PlateSpin Ltd., CiRBA Inc., and VMware, make capacity planning products that automatically gather detailed processing power, memory, disk space, and network I/O consumption stats. Collect at least 30 days’ worth of numbers to ensure you have a complete view of utilization patterns. Then compare that data to the capacity of your client’s server hardware to determine a realistic consolidation ratio.

Give some thought as well to how you’ll distribute virtual workloads across your customer’s physical servers, Spear suggests. For example, placing the client’s busiest apps on different host machines can help reduce performance degradation. Be sure to leave some unused capacity on physical servers as well. That will keep you from running out of resources during utilization spikes, and also give you room for growth later when new applications come on line. Last but not least, confirm with your client’s application vendors that their software will function properly under virtualization. “We still run into the occasional vertical application [manufacturer] that says [they] don’t support VMware,” notes Oster. And be sure to perform plenty of lab testing as well. Just because a software maker says you can run its product on a virtual machine doesn’t mean clients will like the performance they get, Chen observes.

MIGRATION AND DEPLOYMENT
Converting a physical machine into a virtual one used to be a tedious undertaking involving lots of software installation and manual data uploads. Nowadays, numerous companies sell physical-to-virtual (p-to-v) migration tools that automate the entire process. Still, while such products are real time savers, they’re far from perfect. “There’s a lot of software out there that claims to do p-to-v with a click of a button,” Oster says. “In our experience, about 80 percent of that stuff works 80 percent of the time.” Plan on virtualizing at least a few physical servers the old-fashioned way, Oster warns.

In addition, set aside some testing time to verify
that virtualization hasn’t introduced cracks in your client’s security and compliance controls. Generally speaking, virtual servers are as secure as physical ones, but your customer will probably want proof. “You have to go through a process of validation,” says Strohl of Entisys Solutions. Installing extra security software specifically designed for virtual environments is also a good idea. “You want to make sure you’re securing the environment at the hypervisor level,” Strohl notes. Catbird Networks Inc. and Blue Lane Technologies Inc. are two of many companies that make hypervisor security products.

SYSTEM ADMINISTRATION
Many businesses expect virtualizing their servers to lighten their management burden. In fact, however, virtualization yields a mixed bag administratively. Sure, you’ll have fewer physical servers to maintain, but that only makes keeping them up and running more urgent than ever. “If one box goes down in the old days, it’s a pain in the neck but it’s not the end of the world,” Oster notes. “If one box goes down now, it takes a lot with it.”

Similarly, while virtualization turns once-laborious tasks like provisioning and configuring servers into point-and-click tasks, it doesn’t make administering operating systems and applications any easier. Software must be patched and updated just as often on virtual machines as on physical ones, Info-Tech’s Sloan observes, which is why he counsels newcomers to virtualization against laying off any server techs. “You’re going to need the people and tools to maintain the same number of servers,” he says.

Meanwhile, virtualization obliges end users and IT partners alike to acquire a whole new set of administrative skills. For example, a task as seemingly straightforward as tracking a network’s topology will pose new challenges under virtualization, given how easy it is to move virtual machines from one host machine to the other. “The way [virtual servers] are interconnected can change very rapidly,” Chen notes. “You have to be aware of that and know how to troubleshoot it.”