For the purpose of optimizing the performance separation according to the usage status of the protocol and the storage system performance, in a storage system 1 including multiple storage devices 2400 which includes a storage controlling unit 2410 performing data write to or data read from a storage drive 2200 according to data input/output requests from an external device 1000 and a protocol processing unit 2514 that responds to a processing result for the input/output requests to the external device 1000 and is capable of responding to data input/output requests transmitted from the external device 1000 following at least two or more protocols, in which each of the storage devices 2400 includes a cluster processing unit 2516 configuring clusters 2811 with the other storage devices 2400 for the external device 1000 and a cluster processing unit 2516, the cluster processing unit 2516 is set to configure cluster groups 2812 for each protocol.