Throttling Snapshot Copies During Consistency Group Creation

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Solution Overview

Problem

Point-in-time snapshot copy operations in data replication environments can disrupt consistency and increase recovery point objectives (RPO) when performed consecutively, affecting data consistency and system recovery.

Innovation Solution

A method where a master process determines if a consistency group has not been created within a predetermined time, sending a request to a subordinate process to create the group, marking logical storage volumes to prevent snapshot copies, creating the consistency group, sending it to a destination site, and then allowing snapshot copies, ensuring consistency and managing RPO.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If point-in-time snapshot copy operations are performed consecutively, then data preservation and system protection are improved, but data consistency is degraded and recovery point objective (RPO) increases

Engineering Contradiction:

Improvedata preservationVSAvoiddata consistency

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The system preemptively prevents snapshot copy operations from interfering with consistency group creation by implementing a detection mechanism. When a snapshot operation is detected during consistency group creation, the system suspends or delays the snapshot operation to avoid disrupting the consistency group formation process, thereby maintaining data consistency while still preserving data protection capabilities

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The system implements a feedback mechanism that continuously monitors the state of logical storage volumes and consistency groups. When a snapshot operation is requested, the system checks whether a consistency group is currently being created, and based on this feedback, dynamically adjusts whether to allow or block the snapshot operation, ensuring data consistency is maintained

Inventive Principle:

Principle #23Feedback

2Reliability

If point-in-time snapshot copy operations are performed consecutively, then data preservation is improved, but recovery point objective (RPO) increases

Engineering Contradiction:

Improvedata preservationVSAvoidrecovery point objective

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system preemptively prevents snapshot operations that would occur during consistency group creation, as these operations would increase RPO. By blocking snapshot operations during the critical consistency group creation window, the system ensures that snapshots are only taken when data consistency is guaranteed, thereby minimizing RPO while maintaining data preservation

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The system performs preliminary checks before allowing snapshot operations to determine whether a consistency group exists or is being created. This preliminary action ensures that snapshot operations are scheduled at optimal times when data consistency is maintained, preventing unnecessary RPO increases

Inventive Principle:

Principle #10Preliminary action

3Stability of the object's composition

If consistency group creation is enforced mandatorily, then data consistency is improved, but system operation complexity increases

Engineering Contradiction:

Improvedata consistencyVSAvoidsystem operation

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The system implements self-service mechanisms where the storage system automatically detects when consistency group creation is needed and enforces it without requiring complex manual intervention. The master process automatically identifies when snapshot operations are attempted during consistency group creation and blocks them, simplifying the overall system operation while maintaining data consistency

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system integrates consistency group management and snapshot operation control into a unified process. The same infrastructure that manages consistency groups also automatically controls snapshot operations, eliminating the need for separate complex control mechanisms and reducing overall system operation complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20210232316A1Throttling a point-in-time snapshot copy operation within a data consistency application

Publication Date: 2021.07.29 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

A computer-implemented method according to one embodiment includes determining that a consistency group has not been created within a predetermined period of time; sending a request to create the consistency group, where the request includes an indication that a creation of the consistency group is mandatory; identifying one or more logical storage volumes associated with the request to create the consistency group; marking each of the identified one or more logical storage volumes to indicate that a point-in-time snapshot copy operation is not allowed for the one or more logical storage volumes; creating the consistency group; sending the consistency group from a source site to a destination site; and removing the marking from each of the identified one or more logical storage volumes to indicate that a point-in-time snapshot copy operation is allowed for the one or more logical storage volumes.