A rack-mount system includes a data center manager and a rack which contains a plurality of electronic devices, a rack management controller and a plurality of power supplies. Before a specific electronic device performs a booting procedure, related booting parameters of the specific electronic device are accessed. The data center manager or the rack management controller is configured to calculate the amount of power required for the specific electronic device to perform the booting procedure according to the accessed booting parameters. The rack management controller is configured to control the number of activated power supplies among the plurality of power supplies according to the calculated amount of power.