Patent ID: 8117161

Claim:
A storage system comprising: a computer; a storage device for storing a file; a plurality of file systems for managing the file; and a plurality of NAS servers that control access from a client to the file systems via a global namespace formed by grouping local namespaces for the plurality of file systems; wherein the NAS servers are configured to accept instruction from the computer, to obtain snapshots of the file systems; the NAS servers are configured to obtain the snapshots of the file systems, and inform the computer of snapshot identifiers and of local paths of the snapshots; the computer is configured to make snapshot management information including global paths of the snapshots based on each of the snapshot identifiers and each of global paths of the file systems corresponding to the snapshots, so that both of the global paths of the file systems and the global paths of the snapshots are configured on the same global namespace simultaneously, with a directory configuration of the snapshots being same in configuration layout as a directory configuration of the file systems; the NAS servers are configured to receive the snapshot management information from the computer; and at least a sub-plurality of the NAS servers operate in synchronization with each other and each NAS server of the sub-plurality creates snapshots at a predetermined timing.