A method for controlling a fan module mounted in a region of a server rack. The method is implemented by a controller unit including a RMC and a region controller that corresponds to the region, and includes: receiving by the region controller temperature data from the server; determining by the region controller whether the RMC operates in a normal state; when the determination is affirmative, transmitting by the region controller the temperature data to the RMC, and controlling by the RMC a fan speed of the fan module according to the temperature data; and when the determination is negative, controlling by the region controller the fan speed according to the temperature data received from the server.