
by Angela Miller
With the focus ever increasing on energy efficiency in the data center, the topic of virtualization takes center stage for many organizations. Both the performance of the newly-launched VMWare stock on the New York Stock Exchange (from around $29 at IPO to almost $68 today) and Microsoft’s impending push into the virtualization arena demonstrate that virtualization will be a hot topic over the next year.
But the benefits of virtualization are not limited to large data centers, and many organizations miss out on the energy efficiency and cooling benefits of deploying virtualization even in their small IT shop.
According to Gartner, server virtualization is just entering the peak of the hype cycle and it is 2-5 years from ‘mainstream adoption.’ This means that over the next couple of years, IT managers will watch as over 50 vendors vie for marketshare in this re-energized space.
Ironically, virtualization is a mature discipline with over 30 years of history in the IT world. It was a key component of any mainframe deployment as early as the 1970s. But with the proliferation of servers and storage devices and burgeoning IT data centers, virtualization has come around again as a way to more effectively utilize the IT resource.
The impact of virtualization on the environment may not be immediately obvious. But think of it this way: in a company where the trend is for users to specify they must have servers ‘dedicated’ to their function, virtualization is a way to segment pieces of the IT infrastructure to provide those dedicated services without requiring the purchase of separate machines. One powerful server can be segmented into dedicated, non-overlapping functions.
This is a powerful utility, especially when you consider that according to various studies the average usage on a dedicated, stand-alone, functional server is less than 10%.
Virtualization comes in many flavors, from server virtualization through hardware and software, to storage virtualization, to the ability to combine many machines into one virtual device.
Server Virtualization
Server virtualization is either hardware, software, or processor-based. In a hardware scenario, software like VMWare is installed at an operating system layer and allows ‘emulation’. Emulation simply means that a server running Linux for example could also run Microsoft Windows inside of a window within Linux. The basic idea behind this virtualization is that the intermediate software intercepts calls from the emulation window and translates those calls into the underlying operating system to pass to the hardware. The virtualization tool simply serves as a translator between the different environments.
There are many reasons to do this – even at a desktop level. For instance, if you are a small business and you have chosen Apple as your platform, you can install tools to allow you to still run Microsoft Windows within a window on the Apple platform. A small business might do this when they are required to use a particular Windows-based tool to interact with a client and do not wish to procure a new machine. From an environmental perspective, emulation allows companies large and small to run multiple operating systems without requiring acquisition of additional hardware.
The second approach to virtualization is to segment the device into multiple operating systems and allowing these environments to operate independently and simultaneously on one device. In this scenario, the server would run both Linux and Windows at the same time and there would be no conversation between the operating environments – each would make calls to the hardware separately and natively. This approach grew more popular with the release of blade type servers by companies like IBM, HP, Dell and Sun.
Blade servers are quite effective in the data center from an environmental perspective. They are typically stripped of redundant components like power supplies. They are compact and have a small impact on the data center physical footprint. And they are efficient because many servers share so many components. Less waste, less energy, less real estate … all good things from an environmental perspective. (One potential downfall of a densely-populated blade server environment is cooling cost. We’ll cover this in a separate post.)
At the component level, some processors by Intel and AMD now come with native functionality to support virtualization. With newer multi-core, multi-threaded processors, the processor can deliver on the virtualization promise by increasing performance by 3-5 times within one processor (according to IDC). Given the heat generation of the processor, the ability to minimize the number of required processors is highly desirable from an environmental perspective.
Server virtualization clearly delivers significant energy savings to companies that can consolidate their environment effectively.
Storage Virtualization
Like server virtualization, storage virtualization comes in many flavors and tends to be far more complex. The primary theories on storage virtualization are appliance-based, switch-based, and storage-controller based. All three approaches basically rely on mapping tables to route application requests between a ‘virtual’ location and a ‘physical’ location on the disk. Without detailing the specifics in each scenario, the bottom line on storage virtualization is that it allows large data centers the ability to deploy very large, disk-dense devices that again are far more efficient than a distributed set of independent devices.
So to build on the blade server discussion: deploying many stand-alone servers each with their own disk storage that is minimally utilized is far less efficient than installing blade servers without any native storage and then linking them to a large storage array or network as a separate, optimized device.
From an environmental perspective, one can argue which architectural approach to storage virtualization is more efficient, but the use of storage virtualization in any context is far more energy, cooling, and footprint efficient for the enterprise data center.
Conclusion
Server and storage virtualization should be key components to any green IT strategy. Both deliver significant energy and cooling cost savings to the enterprise and SMB through consolidation of resources.
Dig deeper on the issues:
I relied on the following sites for analysis in support of this post:
Vmware
Gartner
IBM
Dell
AMD
Intel
Sun
IDC
ESG
Wikipedia