Patent ID: 7856514

Claim:
A storage system comprising: a basic storage apparatus including a SAS controller, a first SAS expander connected to said SAS controller, and a plurality of first disk devices connected to said first SAS expander; and at least one additional storage apparatus including a second SAS expander, a plurality of second disk drives connected to the second SAS expander, and a register file; wherein the first expander included in the basic storage apparatus and the second SAS expander included in the additional storage apparatus are connected to each other via a network; wherein when the additional storage apparatus is powered-on, the second SAS expander sets an initial value as a SAS identification information of the second SAS expander, wherein the second SAS expander determines whether a serial number of the additional storage apparatus is stored in the register file, wherein the second SAS expander, if the serial number of the additional storage apparatus is stored in the register file, creates a first unique identification information using the serial number, and replaces the initial value with the created first unique identification information, wherein the first SAS expander included in the basic storage apparatus determines whether the SAS identification information of the second SAS expander is the initial value, wherein, if the SAS identification information of the second SAS expander is the initial value the first SAS expander in the basic storage apparatus creates a second unique identification information, replaces the initial value with the created second identification information, and recognizes the created second identification information as the SAS identification information of the second SAS expander in the network and, wherein if the SAS identification information of the second SAS expander is not the initial value the first SAS expander recognizes the created first unique identification information as the SAS identification information of the second SAS expander in the network.