IT professionals may initially be awestruck by the promises of virtualisation, but Gartner analysts warn that awe could turn into upset when organisations start to suffer from seven nasty side effects.
David Coyle, research vice president at Gartner, detailed the seven side effects at the research firm's recent Infrastructure, Operations and Management Summit. While virtualisation promises to solve issues such as under-utilisation, high hardware costs and poor system availability, the benefits come only when the technology is applied with proper care and consistently monitored for change, Coyle said.
Here are the reasons Gartner says virtualisation is no IT cure-all:
1. Magnified failures In the physical world, a server hardware failure typically will mean one server fails and backup servers will step in to prevent downtime. In the virtual world, depending on the number of virtual machines residing on a physical box, a hardware failure could impact multiple virtual servers and the applications they host.
"Failures will have a much larger impact, effecting multiple operating systems, multiple applications and those little tiny fires will turn into big fires fast," Coyle said.
2. Degraded performance Companies looking to ensure top performance of critical applications often dedicate server, network and storage resources for those applications, segmenting them from other traffic to ensure they get the resources they need. With virtualisation, sharing resources that can be automatically allocated on demand is the goal in a dynamic environment. At any given time, performance of an application could degrade, perhaps not to a failure, but slower than desired.
3. Obsolete skills IT might not realise the skill sets it has in-house won't apply to a large virtualised production environment until they have it live. The skills needed to manage virtual environments should span all levels of support, including service desk operators who may be fielding calls regarding their virtual PCs. Companies will feel a bit of a talent shortage when moving toward more virtualised systems, and Coyle recommends starting the training now.
"Virtualised environments require enhanced skill sets, and virtual training across many disciplines," he said.
4. Complex root cause analysis Virtual machines move — that is the part of their appeal. But as Coyle pointed out, it is also a potential issue when managing problems. Server problems in the past could be limited to one box, but now the problem can move with the virtual machine and lull IT staff into a false sense of security.
"Is the problem fixed or did you just lose it? You can't tell in a virtual environment," Coyle said. "Are you just transferring the problem around from virtual server to virtual server?"
5. No standardisation Tools and processes used to address the physical environment can't be directly applied to the virtual world, so many IT shops will have to think about standardising how they address issues in the virtual environment.
"Mature tools and processes must be revamped," Coyle said.
6. Virtual machine sprawl The most documented side effect to date, virtual server sprawl, results from the combination of ease of deployment and lack of life-cycle management of virtual machines. The issue could cause consolidation efforts to go awry when more virtual machines crop up than there are server administrators to manage them.
"The virtualised environment is in constant flux," he said.
7. It may be habit-forming Once IT organisations start to use virtualisation, they can't stop themselves, Coyle said. He offered tips to help curb the damage done from giving into a virtual addition.
"Start small. Map dependencies. Create strong change processes. Update runbooks. Invest in capacity management tools. And test, test, test," he said.