If you are thinking about virtualizing your data center, or just interested in going down the server virtualization route, you might want to check out my latest opinions on the subjet.  For those that either know me or read the VMBlog or Virtualization Report, it is quite evident that I am a huge evangelist of the virtualization technology.  But, that doesn't mean that I don't believe that the technology has a few pitfalls or things to be concerned about.  Dan Knezevic and I have been working in the server virtualization space for around 7 years now.  We've been involved with VMware, Connectix and Microsoft products while each were in their early alpha (pre-beta) stages.  In so doing, we have come across a lot of caveats and things to watch out for. 

In this latest article published on TechTarget Magazine's SearchServerVirtualization site, Dan and I discuss the hidden costs that can be associated with virtualization.  The first of three parts discusses Power and Heat Costs as well as Management Costs.

Here is a snippet of the TechTarget article.  I hope you enjoy it. 

In the rush to consolidate servers and save precious data center space, many companies are turning to virtualization. By consolidating a data center's physical servers into virtualized servers, the enterprise can experience higher server utilization and increased operational efficiency.

Although virtualization brings lots of benefits and features, it is important to keep in mind that virtualization is not the Holy Grail and may not be appropriate for every situation or environment. It does come with some drawbacks. These drawbacks may not be deal breakers, but you should be aware of them before you adopt the technology. In this column, we will look at several key issues that can cause problems in a virtualization adoption.

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Power and heat costs

One of the first problems often overlooked is the high power consumption and high heat output of a physical server hosting multiple virtualized servers. Remember that virtualized servers cause the hardware to run at a higher utilization rate, which means the power required to operate the physical server hardware goes up, as does the heat output.

A physical server running many virtual machines may run at a constant 80% or higher utilization rate, at which point the hardware is pulling quite a bit more power than a non-virtualized server running on average around 15% utilization.

Many data centers are not equipped to deal with the new power requirements that are necessary to support virtual servers. For example, you might need four 20-amp power circuits for each 42U data cabinet that is fully loaded with standard 2U servers, in order to satisfy power needs and to provide power redundancy (the ability to withstand a single circuit failure). This power scheme is actually double the standard power layout, which provisions only two 20-amp power circuits per cabinet.

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You can read the entire first part of the article on TechTarget's SearchServerVirtualization site, here.

About the authors: David Marshall is a senior member of the reference architect team at Surgient, Inc., and he specializes in server virtualization, virtualization applications and Windows administration. He also runs the InfoWorld Virtualization Report, as well as the virtualization news blog, VMBlog.com. David is also a co-author of Advanced Server Virtualization: VMware and Microsoft Platforms in the Virtual Data Center, a book that details years of hands on experience using and implementing server virtualization solutions.

Dan Knezevic is a senior network engineer and a team lead for the data center operations team at Surgient Inc, providing expertise in the data center network and server infrastructure as well as virtualization platforms. He also specializes in network security and enterprise storage solutions. He brings six years of virtualization integration experience in the data center environment.