Patent ID: 7191278

Claim:
A method for data accessing in a computer system comprising a host computer and a storage system coupled to said host computer, said storage system comprises a controller and a logical volume said storage system being coupled to said computer, said method comprising the steps of: issuing an access request from said computer to said storage system by using one of a first path and a second path, both of said first path and said second path corresponds to said logical volume; in said storage system, accessing said logical volume, if said storage system receives an access request via said first path, and in said storage system, executing a predetermined process and accessing said logical volume after the finish of said predetermined process, if said storage system receives an access request via said second path; wherein said storage system comprising a primary volume and a secondary volume, said primary volume and said secondary volume are paired and copy data of said primary volume is stored in said secondary volume, wherein said first path and said second path corresponds to said primary volume, and wherein said predetermined process is splitting the pair between said primary volume and said secondary volume.