A method for managing HDD expanders in a cluster storage system is provided. The method according to one embodiment is implemented by each of the HDD expanders, and includes: indicating a device type of HDD expander to a parent node thereof when a device-type request originates from the parent node; and indicating a device type not of HDD expander to the parent node otherwise. The method according to another embodiment is implemented by each HDD expander connected indirectly to a root node, and includes: indicating a device type not of HDD expander to the root node when a device-type request originates from the root node; and indicating a device type of HDD expander to a node that initiates the device-type request otherwise.