A computer system includes one or a plurality of host computers, a storage system including a disk device having a data volume for reading and writing data by the host computer, and a management computer for connecting the host computer and the storage system. The storage system obtains a snapshot of the data volume at a specific time point, holds the written journal after the specific time point, recovers the snapshot with the snapshot obtained at the time point near a recovery point, as the base, in the recovery, by applying the journal to the snapshot, specifies the journal depending on the snapshot or journal as a releasing target by using an order relationship used for determining the order between the snapshot, serving as the base, in the recovery, and the journal applied to the snapshot upon releasing the snapshot or journal, and releases the specified depending journal together with the snapshot or journal as a releasing target.