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Traditionally, servers were approached with a “one workload, one box” philosophy.
That is, if you needed an e-mail server, you bought a new server. If you needed a file server,
you bought a new server. However, each server is not used often enough to truly justify its
location on a single machine. As mentioned earlier, most servers only operate at about 10 to
15 percent of their total load capacity.
The result of having a server for each network application is server sprawl. In this
section, we’ll talk about the merits of consolidating your servers into fewer machines.

Utilization
Server sprawl can be eliminated by consolidating and virtualizing your physical machines
into virtual machines. Applications such as VMware run independently from the
underlying hardware and are supported on a range of physical servers.
And if you have different operating systems for your different applications, that’s not
a problem. A virtual machine represents a complete system—processors, memory, networking,
storage, and BIOS. This allows you to run Windows, Linux, Solaris, and NetWare operating
systems and applications on the same server. This is illustrated in Figure 11-5.
Normally, a server running a lone application experiences total utilization of 15 percent,
tops. That means all that processing power you paid for is being wasted—and all the power
you’re paying the electric company for to run that machine is also being wasted.

File server E-mail server

Windows Apache web
server 2008 server

Virtualization
consolidates
different
applications and
operating
systems on one
server.
FIGURE 11-5 Consolidation and virtualization allows you to run multiple virtual servers on one machine,
and each server can be a different operating system.