"Micro Cooling Fan" are distributed by layer, each layer in the system set up a group of DC-DC module, for all of the logical layer circuit boards or peripherals supply. Adopted by function in a distributed fashion, the system features for each group using a DC-DC power supply module. "Micro Cooling Fan" using veneer in a distributed fashion. Each system board or a logical disk drive by its own DC-DC module to provide a suitable voltage and current. For example, a file server aforementioned AC distributed power systems can in fact be distributed DC scheme. Here we give "Micro Cooling Fan" in two different scale distributed file servers using board power system design.