Introduction to Virtualization - Oracle Solaris 10 System Virtualization Essentials - page 6

dramatically from previous ones: The two workloads have become slightly more
complex, but they are still two workloads.

Figure 1.3 Multiple Operating System Instances on One Computer

To achieve the consolidation of multiple workloads onto one computer, software
or firmware barriers between the workloads might be used, or entire copies of
operating systems might be running on the system. The barriers separate “vir-
tual environments,” which behave like independent computers to various degrees,
depending on the virtualization technology. Once virtualization is accomplished,
several benefits can be achieved, which fall into two categories:

Cost reductions

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Reduced aggregate acquisition costs of computers

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Reduced aggregate support costs of computer hardware

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Reduced data center space for computers

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Reduced need for electricity to power computers and cooling systems

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In some cases, reduced support costs for operating systems

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In some cases, reduced license and support costs for application software

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Nonfinancial benefits

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Increased architectural flexibility

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Increased business agility due to improved workload mobility

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Of course, nothing in life is free: There is a price to pay for these benefits. Some of
the drawbacks of consolidation and virtualization are summarized here:

Perceived increase in complexity: One physical computer will have multiple
VEs; this is balanced by having fewer computers.

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