OpenSolaris™ Bible

Chapter 17. Virtualization Overview

IN THIS CHAPTER

• Benefits of virtualization

• Types of virtualization

• Comparison of virtualization solutions

• Virtualization and a graphical display

• Virtualization administration

Running many applications and users on a single system has long been a common practice, particularly when computers were quite expensive. More recently, as the cost of a standalone system has fallen, it has become common to deploy each application stack on a dedicated machine, even though a majority of these systems are underutilized. In large enterprises, this has led to server-sprawl, with thousands of lightly used systems each running its own software stack. However, as other costs, such as space, power, and cooling, become more significant, this trend is reversing. This has led to a resurgence of interest in virtualization as a solution to consolidating these standalone applications onto shared machines.

Virtualization is a technique long used by operating systems to provide the illusion of exclusive access to shared system resources. For example, when running multiple processes on a single CPU, the operating system uses a form of virtualization to share the CPU among each process. A time-shared machine with multiple users provides another form of virtualization. These simple forms of virtualization are familiar, and largely taken for granted because an operating system such as OpenSolaris is inherently multi-tasking and multi-user. When you start to consolidate workloads and ...