Patent ID: 8364645

Claim:
A data management system comprising: a host apparatus receiving requests from a client apparatus; a first storage apparatus having a first volume for storing a file system composed of a set of files; a second storage apparatus having a second volume; and a file system transfer apparatus for transferring the file system from the first volume of the first storage apparatus to the second volume of the second storage apparatus, when the set of files in the file system has not been accessed for a predetermined period of time, wherein the host apparatus has location information and file system transfer information, the location information is managed in file units and includes an identifier of each file and an identifier of the file system to which the file belongs, and the file system transfer information is managed in file system units and indicates the transfer before and after transfer for the file system and storage location of the file system, wherein when the file system transfer apparatus migrates the file system, the file system transfer apparatus sends a notice of the transfer to the host apparatus, the host apparatus updates the file system transfer information in response to receiving the notice of the transfer, the host apparatus accesses the file in the file system using the location information and the updated file system transfer information.