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CHAPTER

Virtualization

irtualization is the technology that can set you free; it also provides most of the
business drivers to make Green IT happen. No longer do you need to be shackled to
Vdozens, hundreds, or even thousands of physical servers. No longer do you have to
pay exorbitant electrical bills for power and servers. Virtualization allows you to condense
equipment that normally filled racks upon racks in your server room into a much smaller
amount. The benefits include less expense and a much smaller physical footprint.
As with so many other green issues, the benefit is twofold. You save money in electrical
bills to power and cool the servers, and your reduced energy need means less CO is
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generated to produce said electricity. In this chapter, we’ll take a closer look at virtualization
and how the process applies to both your servers and your storage area networks (SANs).

Server Virtualization
Walking into a server room can be a surreal experience. It’s kind of like when Dave
Bowman went inside the HAL 9000 Computer in 2001: A Space Odyssey. Sure, it’s not exactly
the same—you’re not wearing a spacesuit, floating inside a computer bent on your
destruction—but the other stuff is the same. Blinking lights and expensive technology are
everywhere.
In your server room is the hum from the equipment and the white noise of the
constantly spinning fans. You can also feel the electricity as the servers do their work. It’s
sort of awe inspiring until you think about how much electricity you’re using.
Until the day when servers run on perpetual motion, you’ll always use some sort of
electricity. We already talked about the merits of low-power servers, but “low-power”
doesn’t mean “no-power.” Right now the only way to experience a no-power scenario is to
just shut off and unplug your servers.
By consolidating multiple servers onto a single server, that’s what you in essence do—
shut off the power. Instead of your mail server consuming 560 watts of power, once its duties
have been offloaded onto a virtualized server, the old server is consuming 0 watts of power.
Virtualization allows you to take all your existing physical servers and condense them into
an amount about a tenth of the current size—although your mileage may vary, depending on
what kinds of servers you’re using and their importance to your organization.

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