Patent ID: 7428657
Filing Date: 2008-09-23
Classification: G06F

Abstract:
1. A restoring method of storage system comprising a first storage system including a first volume for making a reference to or updating stored data, a second storage system including a second volume for storing a duplicate of the first volume, and a network for connecting the first storage system and the second storage system, in order to make a reference to or to update the data stored in the second volume when a failure occurs in the first volume and to restore the contents of the second volume in the first volume when the first volume recovers from the failure, the restoring method comprising the steps that; the first storage system creates a snapshot of the first volume, the first storage system transmits the snapshot to the second storage system, the first storage system stores a communication history of the snapshot transmitted to the second storage system in a first log storage unit, the second storage system synchronizes the second volume by applying thereto the snapshot received from the first storage system, the second storage system stores a communication history of said received snapshot in a second log storage unit, the second storage system creates a snapshot of the second volume after synchronization, the second storage system accepts a restore command for data from the second volume to the first volume, when the restore command is issued, the first log storage unit is compared with the second log storage unit and a common snapshot among the snapshots of the first volume and the second volume is extracted as a base snapshot, rollback is conducted by applying the base snapshot of the first volume extracted by the first storage system to the first volume, the second storage system transmits the latest snapshot of the second volume to the first volume, and the snapshot received by the first storage system is applied to the first volume.