When it comes to getting rid of physical, bare-metal servers, virtualization pros have a case of wishful thinking.
Virtualization isn't cheap.
- Bob Plankers, virtualization architect at a Midwestern university
Hypervisors are more capable than ever, but physical servers are holding on longer than IT pros expected. According to SearchServerVirtualization.com’s two most recent Virtualization Decisions surveys, respondents’ predictions that the percent of their servers running virtualization would increase over the next 12 months have not come to fruition.
In 2010, 43% of respondents had less than 25% of physical host servers running virtualization, but 78% predicted that the number would increase in the next 12 months.
One year later, 43% of respondents once again reported that less than 25% of physical servers were running virtualization. This time, however, 80% of respondents predicted that proportion would increase in 2012.
These numbers are not necessarily an indicator of stall in pure virtual machine (VM) growth. If an organization has virtualized just 25% of 100 physical servers but runs VMs at a 20:1 ratio on those hosts, it can still be said to be 87% virtualized overall.
But these numbers also appear to indicate that workloads are sticking around on physical servers, even as virtualization becomes the default platform for new applications and vendors talk up the vision of private clouds running in 100% virtual data centers. The responses also indicate that these physical servers are outlasting many IT pros’ estimates of their future lifespan.
Physical servers are sticky
Virtualization pros cite mostly logistical, rather than technical, reasons for why physical servers live on in their environments.
In most shops, virtualization tends to go on new hardware rather than older repurposed servers, leaving virtualization projects at the mercy of hardware refresh cycles.
At Fastenal Company Purchasing, a subsidiary of construction and industrial supplier Fastenal Co., server virtualization required more servers to be connected to shared storage area network (SAN) storage. To consolidate its storage networking and cut costs, Fastenal undertook a Fibre Channel over Ethernet project as it virtualized its servers, which in turn necessitated new server hardware that could support converged network adapters.
Fastenal considered purchasing new hardware for virtualization a sounder investment than repurposing older servers.
“If you’re going to spend money on VMware licenses, you want that hardware at least to stick around for a while,” said David Dulek, senior network administrator for Fastenal.
In the meantime, “if a project went live six months ago and they decided not to virtualize, that host or application is pretty much stuck there…it’ll probably take three to four years to virtualize them,” he said.
That’s a common scenario.
“No one allows for the time needed to build the infrastructure to move to virtual systems,” said Wayne Gateman, an area coordinator of virtualization for a Fortune 15 company in the medical distribution and software field. “Also, companies are not going to say, ‘sure, let’s toss all the equipment we just purchased in the last three years and go virtual,’” he added.
In fact, a lot of organizations choose to leave well enough alone when it comes to legacy apps.
“There are some legacy applications running on Windows 2000 servers, and we’re trying to get everything on the VMware side to [run on] at least [Windows] 2003,” said Chuck Lee, a network engineer for the City of Carlsbad, Calif., which has 120 VMs running on 15 hosts, plus 50 bare-metal servers. “That accounts for about 90% of why we’re not moving. Some of them, the remaining 10%, are because we’re going to retire the remaining applications.”
In other cases, there is a conscious decision to leave an application on a physical server for redundancy’s sake, Lee said. For every two virtualized domain controllers in the city’s environment, one remains physical.
“A large majority of what we have virtualized exists in an HP blade enclosure…if something with that enclosure goes, that could take out potentially all of our environment,” he said.
Meanwhile, people still need domain services running like DNS, DHCP and domain authentication to log into their computers.
No free virtualization lunch
In some cases, users say, virtualizing servers has up-front operational costs that may not fit with a company’s budget cycle, especially in a down economy.
“Virtualization isn’t cheap. It’s one of those things where you have to spend some money on licensing and maybe some new hardware or something like that in order to save money down the road,” said Bob Plankers, a virtualization architect at a Midwestern university. “There are some organizations that aren’t able to wrap their heads around that.”
Politics and business units’ knowledge of technology can also play a role.
“I'm constantly having to remind myself that although virtualization to me is old hat, it's still cutting edge for many business decision makers today,” said Shannon Snowden, a consulting partner with New Age Technologies. “We technologists embrace change and new features, and the [survey] somewhat reflects the optimism that we have toward new technology. We want to believe virtualization is so good that it can change the engrained hardware and software lifecycle process of a business that has already budgeted to their technology plan.”
Beth Pariseau is a senior news writer for SearchServerVirtualization.com. Write to her at firstname.lastname@example.org.