Patent ID: 8315982

Claim:
A file migration method of an information system, the information system including a plurality of Network Attached Storage (NAS) systems, and a computer for reading and writing a plurality of files stored in the NAS systems, wherein the file migration method comprises: executing steps of file migration startup processing; executing steps of file migration processing; and executing steps of file migration termination processing to be executed after execution of the file migration processing, wherein the file migration startup processing comprises: a step of providing a management table which indicates a plurality of relationships between a source system and a destination system; a step of identifying a first NAS system of the NAS systems as the source system of a file migration based on the management table; and a step of identifying a second NAS system of the NAS systems as the destination system of the file migration based on the management table, wherein the file migration processing comprises: a step of acquiring and storing first attribute information including file names, update time information and a Write Only Read Many setting concerning a plurality of files stored in a designated directory of the first NAS system; a step of acquiring and storing second attribute information including file names and update time information concerning a plurality of files stored in the second NAS system; a step of identifying a file to be copied from the first NAS system to the second NAS system based on the difference between the stored first attribute information and second attribute information, and a prescribed rule which preferentially identifies a file with old update time information of the first attribute information as a file to be copied; a step of determining whether the identified file is set Write Only Read Many or not; and a step of copying the identified file from the first NAS system to the second NAS system when the identified file is not set Write Only Read Many, and wherein the file migration termination processing comprises: a step of acquiring and storing third attribute information including file names and update time information concerning a plurality of files to be stored in a designated directory of the first NAS system; a step of acquiring and storing fourth attribute information including file names and update time information concerning a plurality of files stored in the second NAS system based on the file migration processing; and a step of identifying and copying a file to be copied from the first NAS system to the second NAS system based on the difference between the stored third attribute information and fourth attribute information.