1. A file storage system comprising: an edge comprising a local system including a local storage device for storing data and one or more file storage subsystems, which manages the local storage device, coupled to one or more clients and one or more old Network Attached Storage (NAS) devices, a core comprising a remote system configured to provide bases and cloud services for collectively managing servers and storage devices, wherein the core includes an archive system including a remote storage device for storing data and an archive subsystem for managing the remote storage devices, wherein the archive subsystem includes a central processing unit (CPU), a network interface card (NIC), and a host bus adapter (HBA), wherein the NIC is configured to communicate with the one or more clients and the one or more old NAS devices, and wherein the edge and the core are coupled via a network configured to communicate file data between the local system and the archive subsystem, wherein the one or more file storage subsystems are configured to: store, in the local storage device, data of files received from the one or more clients; replicate the files to the archive subsystem; stub one or more files stored in the local storage device; and upon receiving an access request from the one or more clients, read out data of a file related to the access request from the local storage device and transmit the data to the one or more clients if the file is not stubbed, acquire and recall data of a file related to the access request from the archive subsystem and transmit data of the file to the one or more clients if the file is stubbed, wherein the one or more file storage subsystems are configured to manage a plurality of virtual computers including a first virtual computer and a second virtual computer; wherein, when data in the old NAS device is migrated to the local system, the first virtual computer is configured to: receive first data having high access frequency from the old NAS device; receive access request from the clients during receiving the migrated data from the old NAS devices; and replicate the first data to the archive subsystem, wherein the replicated first data is shared with the edge and the core, allocate storage area for the replicated first data based on the access request, the second virtual computer is configured to: receive second data having low access frequency from the old NAS device; and replicate the second data to the archive subsystem.