Patent ID: 8307019

Claim:
A method for controlling a storage system, comprising: splitting a data array stored in a first file into one or more fragment data arrays that include a first fragment data array; storing a first fragment file that includes the first fragment data array in the first storage area; splitting a data array stored in a second file into one or more fragment data arrays that include a second fragment data array; storing a second fragment file that includes the second fragment data array in the second storage area; creating first feature information of the first file and second feature information of the second file; if the first feature information corresponds to the second feature information, determining whether the first fragment data array matches the second fragment data array; and if the first fragment data array matches the second fragment data array, deleting the first fragment data array, and changing the first fragment file to a stub that indicates the second fragment data array, wherein the first feature information is an identical hash value that is calculated from one or more specific fragment data arrays among the one or more fragment data arrays that include a first fragment data array, and the second feature information is an identical hash value that is calculated from one or more specific fragment data arrays among the one or more fragment data arrays that include a second fragment data array.