A storage apparatus connected to a storage device includes a storage module, a memory for storing data to be copied to the storage device, buffers for temporarily saving the data, redundantly, the saved data stored in one of the buffers being recoverable by the data stored in the rest of the buffers, and a control module for executing, storing the data of write request to the storage module and the memory, copying the data to the storage device, saving the data to the buffer when an using rate of the memory is greater than a predetermined rate, writing the saved data stored in the buffer to the memory when an using rate of the memory is not greater than the predetermined rate, detecting a failure of the buffers, and rebuilding the saved data stored in the one of the buffers based on an using state of the buffers.