Virtualisation can help IT managers allocate more resources with less hardware, but not without introducing a slew of management challenges.

Server virtualisation makes it possible to run multiple applications and operating systems on fewer hardware resources, which appeals to many IT managers looking to improve utilisation. According to a recent Forrester Research poll, respondents have virtualised about one-quarter of their servers and plan to have close to 50 percent virtualised in two years. As enterprise IT teams look to broaden their server virtualisation deployments, it’s important to get in front of the management challenges, according to industry watchers and IT managers.

“Virtualisation is a rather addictive technology and IT organisations are spinning out virtual machines faster then they can manage them. The technology warrants a management investment from the start," says Stephen Elliot, a research director with IDC.

For those who are struggling with how to manage virtual machines, here are answers to six important questions.

  • What’s so tough about managing virtual servers?

  • How do I curb virtual server sprawl?

  • Are traditional management tools good enough for virtual servers?

  • Can tools that come bundled with virtualisation hypervisors do the job?

  • Should I wait for Microsoft to deliver its virtualisation hypervisor?

  • What are my freeware and open source options for managing virtual servers?

1. What’s so tough about managing virtual servers?

Some will tell you that managing virtual machines varies little from managing physical servers, and others will say it depends on what you're managing. But all agree you need to have a comprehensive management plan in place before widely deploying virtualisation in production environments.

"Management is not a single discipline. It can range from business continuity planning to patch management," says Andi Mann, a research director at Enterprise Management Associates (EMA). In the case of business continuity planning, virtual servers could be considered easier to manage than physical servers, Mann explains, but when it comes to patching multiple systems, the virtual world introduces complexities. "You can't always be certain if all virtual systems are patched, and obviously that's a problem," Mann says.

Consistency and standardisation also become bigger issues when managing virtual servers alongside physical machines. The perks of virtualisation include easy-to-deploy resources, and that demands IT managers have pre-defined configuration parameters for application and database servers, for instance. Experts say keeping configurations accurate and up-to-date becomes more critical in the virtual environment because configuration drift is more apt to happen on virtual machines. The same goes for patching.

"The focus shifts to managing templates and preventing drift," says Jasmine Noel, principal analyst with Ptak, Noel and Associates. IT managers would ideally create a standard template that details the operating system, vendor software, patch levels, custom code and more. The template would be maintained so that every new virtual server deployed remained consistent with the predefined standard. Patching would also become part of the template, Noel says.

Beyond maintenance and availability management, another key management issue is performance. The complexity of a virtual environment makes determining the root cause of performance issues a more daunting task, industry watchers say.

"Performance management becomes trickier because for the more difficult problems you'll need to understand how physical server issues manifest in the [virtual machines] and vice versa," Noel says.