IMPLEMENTING SNAPSHOT SETS FOR CONSISTENCY GROUPS OF STORAGE VOLUMES
First Claim
1. A method of implementing snapshot sets for consistency groups of storage volumes in a data storage system, comprising:
- forming a consistency group of storage volumes on the data storage system, the consistency group having a data structure;
creating, at a first point-in-time (PIT), a first set of snapshots of the storage volumes in the consistency group;
generating first snapshot metadata for each snapshot in the first set of snapshots, the first snapshot metadata including an identifier of the first set of snapshots and an identifier of the consistency group;
incorporating a snapshot set list including a first snapshot set node into the data structure of the consistency group, the first snapshot set node including the identifier of the first set of snapshots and a first pointer to a first storage volume list of the storage volumes having the respective snapshots in the first set of snapshots; and
performing at least one of (i) adding an additional storage volume to the consistency group, and (ii) removing a respective storage volume from among the storage volumes in the consistency group, without deleting any of the snapshots in the first set of snapshots in the consistency group.
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Abstract
Techniques for implementing snapshot sets for consistency groups of storage volumes in data storage systems. For each snapshot in a snapshot set of a consistency group, metadata is expanded to include a snapshot set identifier, and a consistency group identifier. The data structure of the consistency group is enhanced to include a snapshot set list, which includes the snapshot set identifier(s) of the consistency group, and a pointer to a storage volume list that contains names of storage volumes with snapshots in the snapshot set(s). By expanding the metadata of each snapshot in a snapshot set, and enhancing the data structure of each consistency group with snapshot set(s), relationships between snapshots, snapshot sets, consistency groups, and storage volumes can be readily maintained, allowing storage volumes to be added to and/or removed from consistency groups without having to delete snapshots of the storage volumes and/or snapshot sets of the consistency groups.
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Citations
20 Claims
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1. A method of implementing snapshot sets for consistency groups of storage volumes in a data storage system, comprising:
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forming a consistency group of storage volumes on the data storage system, the consistency group having a data structure; creating, at a first point-in-time (PIT), a first set of snapshots of the storage volumes in the consistency group; generating first snapshot metadata for each snapshot in the first set of snapshots, the first snapshot metadata including an identifier of the first set of snapshots and an identifier of the consistency group; incorporating a snapshot set list including a first snapshot set node into the data structure of the consistency group, the first snapshot set node including the identifier of the first set of snapshots and a first pointer to a first storage volume list of the storage volumes having the respective snapshots in the first set of snapshots; and performing at least one of (i) adding an additional storage volume to the consistency group, and (ii) removing a respective storage volume from among the storage volumes in the consistency group, without deleting any of the snapshots in the first set of snapshots in the consistency group. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A system for implementing snapshot sets for consistency groups of storage volumes in a data storage system, comprising:
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at least one memory; and at least one processor operative to execute instructions out of the at least one memory; to form a consistency group of storage volumes on the data storage system, the consistency group having a data structure; to create, at a first point-in-time (PIT), a first set of snapshots of the storage volumes in the consistency group; to generate first snapshot metadata for each snapshot in the first set of snapshots, the first snapshot metadata including an identifier of the first set of snapshots and an identifier of the consistency group; to incorporate a snapshot set list including a first snapshot set node into the data structure of the consistency group, the first snapshot set node including the identifier of the first set of snapshots and a first pointer to a first storage volume list of the storage volumes having the respective snapshots in the first set of snapshots; and to perform at least one of (i) adding an additional storage volume to the consistency group, and (ii) removing a respective storage volume from among the storage volumes in the consistency group, without deleting any of the snapshots in the first set of snapshots in the consistency group. - View Dependent Claims (15, 16, 17)
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18. A computer program product having a non-transitory computer readable medium that stores a set of instructions to implement snapshot sets for consistency groups of storage volumes in a data storage system, the set of instructions, when carried out by computerized circuitry, causing the computerized circuitry to perform a method of:
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forming a consistency group of storage volumes on the data storage system, the consistency group having a data structure; creating, at a first point-in-time (PIT), a first set of snapshots of the storage volumes in the consistency group; generating first snapshot metadata for each snapshot in the first set of snapshots, the first snapshot metadata including an identifier of the first set of snapshots and an identifier of the consistency group; incorporating a snapshot set list including a first snapshot set node into the data structure of the consistency group, the first snapshot set node including the identifier of the first set of snapshots and a first pointer to a first storage volume list of the storage volumes having the respective snapshots in the first set of snapshots; and performing at least one of (i) adding an additional storage volume to the consistency group, and (ii) removing a respective storage volume from among the storage volumes in the consistency group, without deleting any of the snapshots in the first set of snapshots in the consistency group. - View Dependent Claims (19, 20)
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Specification