Patent ID: 8122151

Claim:
A storage system, comprising: a storage medium for storing data; a plurality of ports for connection to a network; and a control section for controlling input of data to and output of data from the storage medium and transmission and reception of data via the plurality of ports, wherein: the storage medium provides a storage area for storing data written by a computer; the network is connected to another storage system; the network includes a plurality of data transfer paths extending from the plurality of ports to the another storage system; the plurality of ports include a first port, a second port, and a third port; the plurality of data transfer paths include a first data transfer path extending from the first port to the another storage system, a second data transfer path extending from the second port to the another storage system, and a third data transfer path extending from the third port to the another storage system; and the control section is configured to: write, after receiving a request to write data into the storage area from the computer, data into the storage area; and divide a copy of data written in the storage area into a plurality of transfer units, and transmit a request to write the plurality of transfer units from the plurality of ports to the another storage system, in an order of the received request; acquire a time that elapses after each of the ports transmits the request to write the plurality of transfer units until receiving a response to the transmitted request from the another storage system; calculate a response time of each of the data transfer paths by subtracting a time required for the another storage system to write the plurality of transfer units, which is included in the response, from the acquired time; calculate a first ratio by dividing a mean value of the response times of the plurality of data transfer paths by the response time of the first data transfer path; calculate a second ratio by dividing a mean value of the response times of the plurality of data transfer paths by the response time of the second data transfer path; transmit, if the first ratio is smaller than a predetermined threshold value, the plurality of transfer units from the plurality of ports excluding the first port; transmit, if the first ratio is larger than the predetermined threshold value and smaller than the second ratio, the plurality of transfer units from the plurality of ports so that a number of the transfer units transmitted from the first port is smaller than a number of the transfer units transmitted from the second port; and transmit, if a failure occurs in the third data transfer path after the plurality of transfer units are transmitted from the plurality of ports excluding the first port, the plurality of transfer units from the plurality of ports which exclude the third port and include the first port.