Snapshot reconstruction from an existing snapshot and one or more modification logs
First Claim
Patent Images
1. A method, comprising:
- creating a first snapshot of a data volume;
logging modifications to the data volume in one or more modification logs, wherein the modifications occur subsequent to said creating the first snapshot, wherein the one or more modification logs identify a post-modification value of at least one modified block of the data volume;
creating a second snapshot subsequent to said creating the first snapshot; and
if the first snapshot is deleted, reconstructing the first snapshot by modifying the second snapshot according to the one or more modification logs.
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Abstract
A deleted snapshot of a data volume may be reconstructed from an existing snapshot and one or more modification logs. For example, modifications to the data volume that occur subsequent to creation of a first snapshot may be logged in a modification log. If the first snapshot is deleted, the first snapshot may be reconstructed by modifying a second snapshot, created after the first snapshot, according to the modification log in order to undo any modifications made to the data volume prior to creation of the second snapshot and after creation of the first snapshot.
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Citations
25 Claims
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1. A method, comprising:
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creating a first snapshot of a data volume; logging modifications to the data volume in one or more modification logs, wherein the modifications occur subsequent to said creating the first snapshot, wherein the one or more modification logs identify a post-modification value of at least one modified block of the data volume; creating a second snapshot subsequent to said creating the first snapshot; and if the first snapshot is deleted, reconstructing the first snapshot by modifying the second snapshot according to the one or more modification logs. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A computer system, comprising:
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one or more microprocessors; a memory coupled to the one or more microprocessors, the memory storing program instructions executable by the one or more microprocessors to; create a first snapshot of a data volume; log modifications to the data volume detected subsequent to creation of the first snapshot, including a post-modification value of at least one modified block of the data volume, in one or more modification logs; create a second snapshot; and if the first snapshot is deleted, reconstruct the first snapshot by modifying the second snapshot according to the one or more modification logs. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A computer readable medium including program instructions executable to:
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create a first snapshot of a data volume; log modifications to the data volume detected subsequent to creation of the first snapshot, including a post-modification value of at least one modified block of the data volume, in one or more modification logs; create a second snapshot; and if the first snapshot is deleted, reconstruct the first snapshot by modifying the second snapshot according to the one or more modification logs. - View Dependent Claims (20, 21, 22, 23)
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24. A computer system, comprising:
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one or more storage devices, wherein a data volume is stored on one or more of the storage devices, and wherein a plurality of snapshots of the data volume are stored on one or more of the storage devices; a snapshot manager coupled to the one or more storage devices, wherein the snapshot manager is configured to reconstruct a deleted snapshot of the data volume from one of the plurality of snapshots; a modification manager coupled to the one or more storage devices and configured to log modifications to the data volume, including a post-modification value of at least one modified block of the data volume, relative to a creation time of each of the plurality of snapshots and a creation time of the deleted snapshot; wherein the snapshot manager is configured to reconstruct the deleted snapshot by modifying the one of the plurality of snapshots according to the modifications logged by the modification manager.
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25. A system, comprising:
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means for storing a portion of a plurality of snapshots of a data volume; means for logging modifications to the data volume, including a post-modification value of at least one modified block of the data volume, relative to a creation time of each of the plurality of snapshots; means for reconstructing a deleted snapshot of the plurality of snapshots from an existing snapshot of the portion of the plurality of snapshots by modifying the existing snapshot according to the modifications logged subsequent to a creation time of the deleted snapshot and prior to a creation time of the existing snapshot, wherein the creation time of the deleted snapshot is earlier than the creation time of the existing snapshot.
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Specification