Method and system for restoring a volume in a continuous data protection system
First Claim
1. A method for synchronizing a secondary volume with a primary volume in a continuous data protection system, comprising the steps of:
- scanning a region of the primary volume;
comparing the scanned region with a corresponding region of the secondary volume;
storing an identification of the scanned region in a compare delta map when the comparing step results in a discrepancy between the scanned region and the corresponding region; and
copying data from the primary volume to the secondary volume, using the compare delta map as a guide to locate the data to copy.
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Abstract
A method for synchronizing a secondary volume with a primary volume in a continuous data protection system begins by scanning a region of the primary volume, which is then compared with a corresponding region of the secondary volume. An identification of the scanned region is stored in a compare delta map when the comparison results in a discrepancy between the scanned region and the corresponding region. Data is copied from the primary volume to the secondary volume, using the compare delta map as a guide to locate the data to copy. If the data protection system has failed just prior to the restore process being initiated, it is termed a re-baseline, and the entire primary volume is scanned. If the data protection system is active prior to the restore process being initiated, it is termed a re-synchronization, and is optimized by scanning only select regions of the primary volume.
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Citations
24 Claims
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1. A method for synchronizing a secondary volume with a primary volume in a continuous data protection system, comprising the steps of:
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scanning a region of the primary volume;
comparing the scanned region with a corresponding region of the secondary volume;
storing an identification of the scanned region in a compare delta map when the comparing step results in a discrepancy between the scanned region and the corresponding region; and
copying data from the primary volume to the secondary volume, using the compare delta map as a guide to locate the data to copy. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for restoring a primary volume from a secondary volume in a continuous data protection system, comprising the steps of:
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selecting a snapshot of the primary volume to be restored; and
loading the snapshot from the secondary volume to the primary volume.
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13. A system for synchronizing a secondary volume with a primary volume in a continuous data protection system, comprising:
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scanning means for scanning a region of said primary volume;
comparing means for comparing said scanned region with a corresponding region of said secondary volume;
storing means for storing an identification of said scanned region in a compare delta map when said comparing means returns a discrepancy between said scanned region and said corresponding region; and
copying means for copying data from said primary volume to said secondary volume, using said compare delta map as a guide to locate the data to copy. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A system for restoring a primary volume from a secondary volume in a continuous data protection system, comprising:
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at least one snapshot of said primary volume, each of said at least one snapshots corresponding to a different point in time;
selecting means for selecting one of said at least one snapshots to be restored; and
loading means for loading said selected snapshot from said secondary volume to said primary volume.
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Specification