A method for performing data-accessing management in a storage server and associated apparatus such as a host device, a storage device, etc. are provided. The method includes: in response to a client request of writing a first set of data into the storage server, utilizing the host device within the storage server to trigger broadcasting an internal request corresponding to the client request toward each storage device of a plurality of storage devices within the storage server; and in response to the internal request corresponding to the client request, utilizing said each storage device of the plurality of storage devices to search for the first set of data in said each storage device to determine whether the first set of data has been stored in any storage device, for controlling the storage server completing the client request without duplication of the first set of data within the storage server.