Provided is a storage system that includes a first cluster and a second cluster and that controls a storage device. The first cluster has a first processor and a first memory, and the second cluster has a second processor and a second memory. The second processor includes an error check module for verifying a DMA controller and a guarantee code. The first cluster adds the guarantee code to write data and stores the same in the first memory. The second cluster activates the DMA controller, reads the write data and the guarantee code from the first memory, causes the error check module to verify the guarantee code, and then stores the same in the second memory.