A method of managing a generation of backup data in a storage system is carried out by a storage control device. The backup data is data generated in each of a plurality of pairs originating from one volume. The method includes: receiving, from a host computer, a split request for stopping synchronization between a primary volume and a secondary volume in one of the pairs, and version information about the split; performing a split process in which a backup between the primary volume and the secondary volume of the pair is performed in response to the split request and the synchronization of the pair is stopped; and storing, for each pair, version information of the split process in a predetermined storage section.