Patent ID: 8725695

Claim:
A storage system, which comprises a second NAS (Network Attached Storage) storage apparatus and a third NAS storage apparatus for migrating an object managed by a first NAS storage apparatus, wherein the second NAS storage apparatus has a processor and a storage medium capable of storing data, and wherein the processor of the second NAS storage apparatus is configured to: with respect to an object for which a migration from the first NAS storage apparatus has been started, create management information with respect to the object and custom information including path information of an object path of the first NAS storage apparatus, and store the management information and the custom information in the third NAS storage apparatus prior to migrating an object entity to the third NAS storage apparatus; and after receiving the object entity from the first NAS storage apparatus and migrating the object entity to the third NAS storage apparatus, store path information of the object entity of the third NAS storage apparatus in the management information of the object, and reflect the management information in the third NAS storage apparatus, wherein the custom information includes information whether the object entity is stored in the third NAS storage apparatus, and wherein, in a case where the second storage apparatus recovers from the failure, the processor is configured to: determine whether the third NAS storage apparatus stores the object entity according to the custom information; acquire object information of the object and the object entity from the first NAS storage apparatus, if the third NAS storage apparatus does not store the object entity; and acquire the object information of the object and the object entity from the third NAS storage apparatus, if the third NAS storage apparatus stores the object entity.