Consistency Group Management for Storage Snapshot Mount Points

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Solution Overview

Problem

Conventional snapshot copy utilities face difficulties in creating and managing consistency groups of snapshot mount points, which are essential for maintaining data integrity and efficiency in storage systems.

Innovation Solution

A method is introduced to manage consistency groups by creating a set of snapshot mount points, where each mount point represents a different point in time copy of a logical object, enabling efficient data storage and improved performance by allowing the creation and management of consistent snapshots.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional snapshot copy utilities are used, then snapshot creation is possible, but consistency group management and write-order consistency across logical volumes cannot be maintained

Engineering Contradiction:

Improvedata integrityVSAvoidconsistency group management

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple snapshot mount points into a consistency group, treating them as a unified logical structure. This allows the system to maintain write-order consistency across multiple logical volumes by managing their snapshots collectively rather than independently, thereby improving data integrity while simplifying the management complexity through consolidation.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent segments the consistency group into individual snapshot mount points that can be independently managed while maintaining overall consistency. This segmentation allows flexible management of different logical volumes within the consistency group while preserving write-order consistency, resolving the contradiction between reliability and management complexity.

Inventive Principle:

Principle #1Segmentation

2Quantity of substance

If snapshot copies are created without consistency group management, then storage space is saved, but write-order consistency across logical volumes cannot be ensured

Engineering Contradiction:

Improvestorage spaceVSAvoidwrite-order consistency

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent creates snapshots of logical volumes that copy only the changed blocks since the last snapshot, rather than copying the entire volume. This copying approach saves storage space while the consistency group mechanism ensures write-order consistency is maintained across all snapshots in the group, resolving the contradiction between storage efficiency and data reliability.

Inventive Principle:

Principle #26Copying

3Reliability

If consistency groups of snapshot mount points are created, then write-order consistency is maintained, but storage costs increase

Engineering Contradiction:

Improvewrite-order consistencyVSAvoidstorage space

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent performs preliminary actions by creating snapshots at specific points in time before changes occur. This allows the system to maintain write-order consistency by having pre-created snapshot copies that can be restored or used as baselines, reducing the need for continuous storage allocation and lowering overall storage costs while maintaining reliability.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS8850145B1Managing consistency groups in storage systems

Publication Date: 2014.09.30 EMC IP HLDG CO LLC

AI summary

A method is used in managing consistency groups in storage systems. A consistency group is created from a set of snapshot mount points. A snapshot mount point is a logical object accessible for using a replica of a logical volume. An operation is performed on the consistency group.