Today's common techniques for monitoring the data center environment date from the days of centralized mainframes, and include such practices as walking around with thermometers and relying on IT personnel to feel the environment of the room. But as data centers continue to evolve with distributed processing and server technologies that are driving up power and cooling demands, the environment must be looked at more closely.

Rising power density and dynamic power variations are the two main drivers forcing changes in the monitoring methodology of IT environments. Blade servers have tremendously increased power densities and dramatically changed the power and cooling dynamics of the surrounding environments. Power management technologies have pushed the ability of servers and communication equipment to vary power draw (and therefore heat dissipation) based on computational load. This issue is described in detail in APC White Paper # 43, Dynamic Power Variations in Data Centers and Network Rooms.