Multi-Site Snapshot Reference Locking for Fast Data Failover

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Solution Overview

Problem

Existing data replication methods in multi-site environments suffer from costly and inefficient data transfer due to unnecessary retention of frequent snapshots, failing to meet recovery point objectives (RPO) and leading to potential data loss.

Innovation Solution

Implementing a site ownership tag as an advisory lock in a DR-API protocol to protect common snapshot references, ensuring only incremental changes are replicated, thereby maintaining RPO requirements and preventing accidental deletion or modification of recovery points.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If frequent snapshots are retained between sites, then RPO requirements are satisfied, but network bandwidth is reduced and storage costs increase

Engineering Contradiction:

ImproveRPO satisfactionVSAvoidnetwork bandwidth

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies preliminary action by pre-protecting common snapshot references using ownership tags before failover operations are needed. This ensures that the latest snapshot is already preserved and ready for rapid failover, eliminating the need to retain multiple frequent snapshots while still satisfying RPO requirements.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent extracts only the essential common snapshot reference (protected by ownership tag) from the set of all snapshots, rather than retaining all frequent snapshots. This extraction approach maintains RPO satisfaction while significantly reducing network bandwidth consumption and storage requirements.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If multiple snapshots are retained at each site, then data availability for failover is ensured, but storage overhead increases

Engineering Contradiction:

Improvedata availabilityVSAvoidstorage overhead

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The ownership tag mechanism performs preliminary protection of the common snapshot reference, ensuring data availability is established in advance through a single protected snapshot rather than requiring multiple snapshots to be retained for safety.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent extracts only the necessary common snapshot reference that needs to be preserved for failover, using ownership tags to protect this single critical snapshot. This eliminates the need to store multiple redundant snapshots while maintaining data availability.

Inventive Principle:

Principle #2Taking out (Extraction)

3Loss of energy

If incremental changes are replicated instead of full snapshots, then network costs are reduced, but complexity of managing snapshot references increases

Engineering Contradiction:

Improvenetwork costsVSAvoidsnapshot reference management

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The ownership tag acts as an intermediary mechanism that simplifies snapshot reference management. Instead of complex logic to track and manage multiple snapshot references, the ownership tag provides a straightforward protective layer that automatically ensures the common snapshot reference is preserved and available for failover.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Quantity of substance

If a single snapshot is retained at each site, then storage efficiency is improved, but risk of accidental deletion increases

Engineering Contradiction:

Improvestorage efficiencyVSAvoidsnapshot protection

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The ownership tag provides preliminary protection to the single snapshot reference before any deletion or modification operations can occur. This pre-established protective mechanism prevents accidental deletion while maintaining storage efficiency through single snapshot retention.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The ownership tag serves as an intermediary protective layer between the snapshot and potential deletion operations. This mediator mechanism ensures that even with only a single snapshot retained, the system maintains high reliability by preventing accidental modifications through the ownership tag protection.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12579043B2Managing reference snapshots across multiple sites for efficient failover/failback

Publication Date: 2026.03.17 NUTANIX INC

AI summary

A technique provides network efficient data failover by explicitly protecting one or more common snapshot references at sites of a multi-site data replication environment to improve granularity of control of recovery point objectives (RPO) for data across the sites. A common snapshot reference or recovery point (RP) ensures that, in the event of failure to a site, data designated for failover may be quickly protected by replicating only small incremental changes to the RP so as to maintain RPO requirements across the sites. Illustratively, the technique enhances and extends a disaster recovery (DR) application programming interface (API) protocol through an extension that defines and applies a tag to the RP, wherein the tag enables protection and/or preservation of the RP by ensuring that the sites honor the tag applied to the RP. The tag essentially functions as an advisory lock for the RP that is shared among the sites to prevent deletion of the RP at the sites throughout the duration of the lock.