Abstract: A storage apparatus is connected to a host apparatus and a secondary storage apparatus and includes a memory, a storage device, and a processor. The memory includes a save memory area and a cache memory area that temporarily stores data received from the host apparatus. The storage device stores data that is received from the host apparatus. The processor controls a duplication process for specified data to another storage apparatus at a point in time of a start of duplication, saves a first data block into the save memory area when receiving an update request of the first data block in the cache memory area after the start of duplication, and updates the first data block in the cache memory area to an updated data block.

Abstract: A file management method according to the present invention is based upon a file management method of making a file from a client to a storage device redundant by a certain redundant number and storing the file in the storage device, and the file management method according to the present invention includes a first step of accepting an additional file from the client to the storage device, a second step of comparing capacity of the additional file and unused physical capacity of the storage device and a third step of changing the redundant number of the already stored file, increasing the unused physical capacity and storing the additional file in the storage device when the capacity of the additional file is larger than the unused physical capacity.

Abstract: In a file storage service system, a computer stores files in a hybrid cloud. The computer comprises an extension metadata table which stores file storage conditions and target availability and an arrangement planned cloud table which stores a first identifier of a first cloud included in the hybrid cloud. The computer further comprises: an arrangement number calculation unit which selects a second cloud included in the hybrid cloud and satisfying the storage conditions and stores an identifier of the selected second cloud as the first identifier of the first cloud in the arrangement planned cloud table when availability of the selected second cloud satisfies the target availability; and a file arrangement management unit which stores a file uploaded from a client terminal in the first cloud identified by the first identifier stored in the arrangement planned cloud table by referring to the extension metadata table.