Patent ID: 8234419

Claim:
A storage system comprising: a first storage apparatus that is data I/O for at least one first logical volume configured by using a storage area of a storage device in accordance with a first data I/O request sent from an external device; a second storage apparatus that performs data I/O for at least one second logical volume configured using a storage area of a storage device in accordance with the data I/O request sent from the external device; and a management apparatus that is an information processing apparatus communicatively coupled to each of the external device, the first storage apparatus, and the second storage apparatus, the storage system performing external attachment processing, in which the first storage apparatus stores associations between the first logical volume and the second logical volume in which an entity of data of the first logical volume is stored; upon receipt of the first data I/O request for the first logical volume from the external device, the first storage apparatus transmits a second data I/O request to the second storage apparatus, the second data I/O request being directed to the second logical volume associated with the first logical volume; upon receipt of the second data I/O request, the second storage apparatus performs data I/O for the second logical volume and transmits a response thereto to the first storage apparatus; and, upon receipt of the response, the first storage apparatus transmits a response to the first data I/O request to the external device; and the storage system performing external attachment release processing, in which the management apparatus transmits an instruction to the first storage apparatus to release the association between the first logical volume and the second logical volume, and transmits an instruction to the external device to change a path of the first data I/O request directed to the first logical volume so that the first data I/O request is directly transmitted to the second logical volume as a destination; wherein the storage system further performs external attachment resume processing, in which, after performing the external attachment release processing, the management apparatus acquires the performance information; the management apparatus determines whether or not the external attachment processing is resumed for the first logical volume based on the performance information; in a case where the external attachment processing is determined to be resumed, the management apparatus transmits an external attachment start instruction to the first storage apparatus, the external attachment start instruction ordering the first storage apparatus to store an association between the first logical volume and the second logical volume; and the management apparatus transmits an instruction to the external device to change a path of the first data I/O request directed to the second logical volume so that the first data I/O request is transmitted to the first logical volume as destination.