Method for rolling back from snapshot with log
First Claim
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 5 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.
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Abstract
High speed differential copy can be implemented in the fail-back after disaster recovery when the data of the primary site is protected safely. When a restore command is issued, the common snapshots of the snapshots of the primary site and the secondary site are extracted as the base snapshot by comparing the log tables of the primary site and secondary site. The volume of the primary site is rolled back with the extracted snapshots. The latest snapshot of the volume of the secondary site is transmitted to the primary site and it is applied to the volume of the primary site to synchronize the volumes of the primary site and the secondary site.
232 Citations
16 Claims
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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 5 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;
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A storage system comprising
a volume for storing data, and a control unit for enabling backup of data by creating a snapshot of the volume and then transmitting the snapshot to a second storage system, wherein the control unit comprising a snapshot creating unit for creating a snapshot of the volume, a transmitting unit for transmitting the snapshot to the second storage system, a synchronizing unit for applying the snapshot received from the second storage system to the volume, a first log storage unit for storing a communication history of the transmitted and received snapshot, a receiving unit for receiving a restore command from a management computer, a base snapshot extracting unit for reading, upon acceptance of the restore command, the communication history from the first log storage unit, reading a communication history from a second log storage unit of the second storage system, and extracting the snapshot corresponding to the common communication history from these communication histories as a base snapshot, a rollback instructing unit for instructing the second storage system to conduct rollback with the base snapshot, and a synchronization instructing unit for transmitting the latest snapshot to the second storage system with the snapshot creating unit.
Specification