A primary storage system and a secondary storage system are connected via a copy network in this computer system. This computer system includes a measurement unit for measuring an update data input amount to be input into the primary update data storage area, a calculation unit for calculating a recovery point in each given period of time based on the measured update data input amount and the band of the copy network, and a comparison unit for comparing the calculated recovery point and a target recovery point to be pre-set as a target value for recovering the update data.