Patent ID: 7269667

Claim:
A disk array system comprising: a source storage system; and a target storage system; wherein said source storage system, and said target storage system are connected to one another through a network; wherein said source and target systems each include a storage apparatus, a storage control apparatus, a storage interface unit for connecting between said storage apparatus and said storage control apparatus, and an upper interface unit for connecting with a host computer, said storage apparatus having a first input/output port and a second input/output port for connecting with said storage interface unit; and wherein to migrate said storage apparatus in said source storage system to said target storage system, said disk array performs the steps of: causing said management program to switch from a logical volume of said source storage system to a logical volume of said target storage system to access said logical volume of said target storage system; defining a logical volume, which is on said storage apparatus to be migrated, in said source storage system as an external volume of said target storage system, and setting to receive an access targeted to said logical volume, which is defined on said storage apparatus to be migrated, through said network and through said first input/output port of said storage apparatus to be migrated, as said external volume of said target storage system; connecting said second input/output port of said storage apparatus to be migrated with said storage interface unit in said target storage system, transmitting information on said logical volume on said storage apparatus to be migrated to said target storage system, defining said logical volume on said storage apparatus to be migrated as a logical volume of said target storage system, and setting to receive an access targeted to said logical volume on said storage apparatus to be migrated through said connected second input/output port as said logical volume of said target storage system, said connecting including physically connecting said second input/output port of said storage apparatus to be migrated with said storage interface unit in said target storage system; and blocking said first input/output port of said storage apparatus to be migrated, said first input/output being currently connected to said storage interface unit in said source storage system, said blocking including logically blocking said first input/output port of said storage apparatus to be migrated.