Patent ID: 7587506

Claim:
A computer system, comprising: a data server coupled to a plurality of client computers via an Internet, and comprising a CPU, a memory and a plurality of network interfaces, the CPU executing a virtual data intermediate server and a plurality of virtual storage servers, the memory storing a storage server information including a plurality of first identification path information, each of the plurality of first identification path information identifying one of the plurality of virtual storage servers; and a backup server coupled to the data server via a local area network and sending a backup request and a first file list to the virtual data intermediate server, the first file list including a set of a plurality of file information, each of the plurality of file information including both a second identification path information for identifying one of the plurality of virtual storage servers and a file reference identification used for referring to a file, wherein the virtual data intermediate server receives the backup request and the first file list from the backup server, and compares a plurality of the second identification path information in the first file list to the plurality of first identification path information included in the storage server information, wherein the virtual data intermediate server, if each of the plurality of second identification path information in the first file list corresponds to one of the plurality of first identification path information included in the storage server information, divides the first file list to a plurality of second file lists, each of the plurality of second file lists including one of the plurality of file reference identifications, wherein the virtual data intermediate server transfers a plurality of file transfer request and the plurality second file lists to the plurality of virtual storage servers, each of the plurality of second file lists being transferred to one of the plurality of virtual storage servers, which is identified by one of the plurality of second identification path information in the first file list, wherein each of the plurality of virtual storage servers receives one of the plurality of file transfer request and a corresponding one of the plurality of second file lists, and sends a file, identified by one of the plurality of file reference identifications included in the corresponding one of the plurality of second file lists, to the virtual data intermediate server in response to the one of the plurality of file transfer request and the corresponding one of the plurality of second file lists, and wherein the virtual data intermediate server receives a plurality of files from the plurality of virtual storage servers and sends a set of the plurality of files to the backup server so that the backup server can backup the set of the plurality of files which the backup server request to the virtual data intermediate server by the backup request and the first file list.