Server consolidation is one of the hottest trends in the industry—and for good reason. Although some businesses succeed in deploying servers according to a master plan, most businesses buy and install servers as new projects come along, without thinking about how to manage them. As a result, IT finds itself with a hodgepodge of systems and platforms that must work together. The cost of deploying each new server is relatively small and easily justified, but management costs are often overlooked. However, these costs add up, and although one stone tumbling down a hill draws little attention, eventually you can find yourself in a rock slide.

Enter Server Consolidation
A Gartner study shows that increasing the average number of users per server from 75 to 250 can save 37 percent of server costs. Oracle is a believer: The company expects to save $300 million a year by decommissioning 4000 servers.

Different organizations use different models to express server-consolidation strategies. One of the best models comes from Gartner, which classifies server consolidation (in order of increasing sophistication and expense) as physical, logical, or rational consolidation.

Choose the Best Strategy for Your Environment
Physical consolidation reduces the number of sites at which systems are installed—for example, you can combine departmental servers into a central data center or consolidate many branch office servers into a smaller number of regional sites. By reducing the number of servers, you can reduce operational and administrative expenses, facilitate disaster recovery, and reduce licensing fees. However, physical consolidation typically requires an investment in bigger hardware and increased bandwidth.

Logical server consolidation begins with an inventory of systems and their functions, then combines like systems. For example, if two departments have file and Web servers, you might combine the two departments' file server functions on one system and Web server functions on another, thus simplifying operations with no loss of functionality.

Rational consolidation combines several small systems into one larger system and runs multiple types of workloads on one server. You can implement rational consolidation at the software level (e.g., on Windows 2000 Datacenter Server) by letting the OS manage the resources allocated to each workload, or at the hardware level by dividing the hardware into multiple logical systems (aka partitioning). Well established in the UNIX and mainframe environments, hardware-based partitioning is still fairly new to Windows. The Unisys ES7000 is one Windows system that's capable of hardware-based partitioning. The benefits and relative costs of rational consolidation are essentially similar to those of physical consolidation, but the savings are magnified as the scale increases.

What Are the Benefits and Risks?
Server consolidation has the potential for substantial benefits to an organization's bottom line, but it isn't for everyone. Most organizations would benefit from logical consolidation, which most efficiently uses resources and in the long run results in a more manageable environment. Physical and rational consolidations, however, can have substantial costs. Worse, an ill-conceived consolidation that reduces system responsiveness or availability can wind up costing more than an unconsolidated configuration. Undertaking consolidation might also impede projects that have important business benefits or deprive the organization of competitive advantages. Consolidation isn't a magic bullet for decreasing IT costs. Less can equal more—but only if you're careful.