Storage system, nas server and snapshot acquisition method

Abstract

A storage system including: 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 one or more file systems; wherein, each NAS server includes a memory to store global namespace management information including global paths of the file systems; one NAS server of the NAS servers accepts a request to obtain snapshots of the file systems from external of the storage system; the one NAS server instructs itself and the other NAS servers to obtain snapshots of the file systems; the one NAS server and the other NAS servers obtain the snapshots of the file systems, and inform the one NAS server of snapshot identifiers and of local paths of the snapshots; the one NAS server makes snapshot management information including global paths of the snapshots based on each of the snapshot identifiers received from the other NAS servers and each of the global paths of file systems corresponding to the snapshots, included in the namespace management information so that both 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; and the one NAS server informs the other NAS servers of the snapshot management information.