Considering CostsBy David Strom | Posted 2009-05-12 Email Print
As you dive deeper into virtual machine technology, you need a solid understanding of the issues involved, particularly when you run your VMs on what are called "bare-metal hypervisors."
Another issue certainly is cost, and the tricky part is balancing the more expensive hardware that a beefier server entails with the additional licensing fees that will be required to run guest VMs. “A single physical server running ESX is going to run $5,000 in up-front licensing fees by the time you pay for all the associated VMware management and high-availability suite of software,” claims John Pozadzides, the chief marketing officer of managed services provider Layered Technologies. “Then you have to add the cost of the server hardware and guest VM operating systems.” He recommends looking at Microsoft’s Windows Server Datacenter license because it includes the ability to have unlimited Windows VMs running as guests, and that makes it very attractive for virtual environments.
The next issue with hypervisors is determining what type of attached storage device will deliver the best performance for your VM guests. Segal’s Sokol uses Fibre Attached Technology Adapted disks as second-tier storage, but he found that “FATA performance wasn’t good for running our transactional-based disaster recovery servers.”
Karen Rhodes, a senior sales engineer at Layered Technologies, says, “You need to spend more time thinking about your storage needs and get the best performing disk solution possible because it will be spinning constantly as a result of the increased traffic from all the VM guests.”
Finally, there are specialized tools useful for converting physical to virtual machines and that manage the overall virtual server environment. Segal uses NSI’s DoubleTake for VM Infrastructure “to replicate our VMs over our wide area network and into our off-site disaster recovery center,” says Sokol.
Tim Suttle, the network and technical operations director for nonprofit services firm TechSoup Global in San Francisco, uses VizionCore’s vRanger and vFoglight tools to manage and monitor his company’s ESX servers. “It gives us deeper insight into potential performance bottlenecks and shows us a single pane to better monitor our entire environment,” he says.
Another product is Novell’s PlateSpin, which “can be used to migrate any physical server to a variety of virtual environments, including ESX, Xen Center, Sun and HyperV,” says Rhodes of Layered Technologies. “You don’t have to tie yourself to any vendor, and it’s a very robust and mature technology.” PlateSpin can also be used to convert virtual machines into physical ones, which is useful for debugging operating system issues.