A file system transfer designation section for transferring the file system matching with file system transfer rules from the first volume of the first storage apparatus to the second volume of the second storage apparatus based on the first file system transfer rules, a file system storage information manager for updating storage information of the file system in accordance with transfer of the file system by the file system transfer designation section, and transmitting the updated file system storage information, and a search information manager for updating search information for searching the files based on a file search request from the client apparatus using the file system storage information sent by the file system storage information manager are provided.