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Decentralization versus Centralization > Decentralization versus Centralization - Pg. 12

12 Chapter1·AnIntroductiontoVirtualization In contrast, the table also shows a similarly configured centralized setup of five OS/application instances hosted on a single two-way server with sufficient hardware resources for the combined workload, as shown in Figure 1.3. Although savings are realized by the 5:1 reduction in server hardware, that savings is matched by the savings in software cost (5:1 reduction in physical CPUs to license), supporting infrastructure, power, and cooling. Figure 1.3 A Centralized Five-Server Configuration Two-Way Server Virtual Host 75 % Utilized, 2 FC Switch Ports, 2 Network Ports Network and SAN Switches Storage Arrays and Other Infrastructure W arning When building the business case and assessing the financial impact of virtualization, be sure not to over-commit the hosts with a large number of virtual machines. Depending on the workload, physical hosts can manage as many as 20 to 30 virtualization machines, or as little as 4 to 5. Spend time upfront gathering performance information about your current work- loads, especially during peak hours, to help properly plan and justify your virtualization strategy.