Automatic Unplanned Failover for Multi-Site Storage Systems

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Solution Overview

Problem

Existing multi-site distributed data storage systems face disruptions due to unplanned failures, such as network disconnections and data center failures, which can lead to connectivity issues and require manual intervention for recovery.

Innovation Solution

The implementation of an automatic unplanned failover (AUFO) feature that ensures non-disruptive operations by seamlessly transitioning I/O operations from a primary storage site to a secondary mirrored storage site, even in the presence of multiple failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual intervention is used to handle storage system failures, then system complexity is reduced, but downtime increases and reliability decreases

Engineering Contradiction:

Improvesystem availabilityVSAvoiddowntime

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary actions by pre-configuring mirror copies of data at secondary storage sites and establishing failover capabilities in advance. When a failure occurs, the system can immediately activate the pre-prepared mirror copy without requiring manual intervention, thus reducing downtime while maintaining reliable operation.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If automatic failover is implemented, then downtime is reduced and reliability improves, but device complexity increases

Engineering Contradiction:

Improvesystem availabilityVSAvoidsystem architecture

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system creates mirror copies of data at secondary storage sites, which are exact replicas of the primary data. This copying approach enables automatic failover without complex decision-making logic, as the system simply switches to the pre-existing mirror copy when a failure is detected, thereby improving reliability while keeping the complexity manageable.

Inventive Principle:

Principle #26Copying

3Productivity

If primary storage system continues to serve I/O operations during failure, then productivity is maintained, but data consistency may be compromised

Engineering Contradiction:

ImproveI/O operation continuityVSAvoiddata consistency

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system introduces a mediator component that coordinates between the primary and secondary storage systems during failover. The mediator ensures that I/O operations are properly redirected and that data consistency is maintained by managing the transition process, allowing productivity to be maintained while preserving reliability through controlled handover.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12321246B2Methods and systems for a non-disruptive automatic unplanned failover from a primary copy of data at a primary storage system to a mirror copy of the data at a cross-site secondary storage system

Publication Date: 2025.06.03 NETAPP INC

AI summary

Multi-site distributed storage systems and computer-implemented methods are described for providing an automatic unplanned failover (AUFO) feature to guarantee non-disruptive operations (e.g., operations of business enterprise applications, operations of software application) even in the presence of failures including, but not limited to, network disconnection between multiple data centers and failures of a data center or cluster.