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50 50 P a r t I I : a r t I I : C o n s u m p t i o n I s s u e so n s u m p t i o n I s s u e s

FIGURE 3-2
Consolidating
servers onto a
fewer number of
units conserves
energy.

Old servers virtualized
on a single server
Old servers

If you virtualize your servers, however, advanced clustering technologies allow them to
act as traffic cops and move applications between servers and storage devices with
precision. Regardless of what fails, you can still keep working as normal. Further, this
causes a reduction in the need for hardware, space, and energy usage.
Storage
If your organization uses a lot of direct-attached storage, you will see a huge power savings
if you switch over to a storage area network (SAN). By removing file servers, you see an
instant reduction in power usage.
A SAN also allows you to grow in a logical, efficient manner. With direct-attached
storage, you have to add file servers to your network. If you’ve got a SAN, you just have
to add disks, which is considerably less expensive.

Case Studies
Vanderbilt University’s IT services organization has turned to virtualization with great success.
Realizing that physical servers cost money for power and cooling, as well as their
environmental effects, the university decided to host fewer servers and virtualize. IT services
officials utilized server virtualization for 35 percent of the servers they manage. They estimate
they have been saving 20,575 watts per hour. Officials hope to eventually virtualize 80 percent
of their servers. The state of Oregon is taking on a much larger consolidation project. It is
combining 11 state agency datacenters by June 2009. The plan is for the centers to be
combined at a new datacenter in Salem and involves virtualizing both storage and servers.
The project is estimated to cost $43 million and it is expected to save $10 to $12 million
per year, once finished, and reduce power consumption by up to 35 percent.

Management
In most organizations, computers are used for just 4 hours a day. The additional 20 hours,
those idle machines are still using energy.
Some estimates say that 65 percent of the energy used by computers and monitors is
wasted because workers don’t turn off computers when they leave for the day. Additionally,
half of computer monitors do not have a power management scheme applied, so more
money is wasted when they fail to automatically switch off.