Patent ID: 7444545

Claim:
A computer system comprising a storage system having a volume which is a storage area, a managing computer for managing the storage system, and a host computer for reading and writing data in the volume of the storage system, which are connected via a network: wherein the storage system retains a journal of the data stored in the volume and a volume replicating the data stored in the volume, for restoring the data stored in the volume at any update time point by the journal and the replicated volume; and the managing computer acquires a register creation demand with respect to the volume retaining the journal, the register creation demand including a recovery time objective which is the time of recovery and/or a recovery point objective which is the update time point and a journal retention period which is the period during which the journal is retained, monitors the journal of the data stored in the volume, computes the quantity of the journal, and determines the capacity of the volume for retaining the journal.