In order to reduce the amount of consumption of a back-end bandwidth in a storage apparatus, a computer system includes: a first storage device; and a second storage device that is coupled to the first controller through a first interface and is coupled to the second controller through a second interface. The first controller receives data from a host computer through a first communication channel; write the received data into the first storage device; identify part of the received data as first data, the part satisfying a preset particular condition; and write a replica of the first data as second data into the second storage device. The second controller reads the second data from the second storage device in response to a Read request received from the host computer through a second communication channel; and transmit the second data to the host computer through the second communication channel.