Patent ID: 7797477

Claim:
A method for searching a file from a plurality of files stored in a storage system, the storage system including a plurality of disks storing the plurality of files and a controller coupled to the plurality of disks and controlling to search the file from the plurality of files according to a search request received from a computer, the method comprising the steps of: creating, based upon execution by the controller, an index used for searching the file by selecting a portion of a content of the file used as the index for the file, the portion of the content of the file including life-cycle information indicating one of a plurality of life-cycle periods to which the file presently belongs, the plurality of life-cycle periods including a first period during which the file is updated most frequently, a second period during which the file is referenced more frequently than updated, and a third period during which the file is accessed least frequently; receiving, based upon execution by the controller, the search request including a keyword regarding a certain life-cycle period; searching, based upon execution by the controller, the file according to the search request by retrieving indexes of the plurality of files to find out an index including the life-cycle information indicating the certain life-cycle period specified as the keyword; and returning, based upon execution by the controller, a file name corresponding to the index found in the searching step.