Remote Data Replication Verification Before Role Reversal

Solution Overview

Problem

Existing remote data replication systems face challenges in identifying and correcting data mismatch errors before role reversal events, such as failover or failback, which can lead to data inconsistencies and potential customer data loss.

Innovation Solution

Implementing a data verification process that includes a full scan using Data Integrity Field (DIF) information or a quick scan using metadata signatures to compare data on primary and backup storage arrays, allowing for error identification and correction before role reversal, with the choice of scan method depending on the time available until the event.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a full data scan using DIF information is implemented to compare primary and backup storage arrays, then data verification accuracy is improved, but the time required for verification increases

Engineering Contradiction:

Improvedata verification accuracyVSAvoidverification time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The system implements two levels of verification: a quick scan that checks metadata signatures for all tracks (partial verification), and a full scan that verifies DIF information only for tracks that failed the quick scan (excessive action only where needed). This resolves the contradiction by achieving high verification accuracy without requiring full verification time for all tracks.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The verification process is segmented into two distinct phases: quick scan phase (metadata signature comparison) and full scan phase (DIF information comparison). This segmentation allows the system to quickly filter out matching tracks using lightweight metadata checks, then apply more time-consuming full verification only to suspicious tracks, thereby maintaining high accuracy while reducing overall verification time.

Inventive Principle:

Principle #1Segmentation

2Loss of time

If a quick scan using metadata signatures is implemented for data comparison, then verification time is reduced, but data verification accuracy deteriorates

Engineering Contradiction:

Improveverification timeVSAvoiddata verification accuracy

Core Design Contradiction:

Loss of timeVSMeasurement precision

Solution Approach 1:

The verification process is segmented into two distinct phases: quick scan phase (metadata signature comparison) and full scan phase (DIF information comparison). This segmentation allows the system to quickly filter out matching tracks using lightweight metadata checks, then apply more time-consuming full verification only to suspicious tracks, thereby maintaining high accuracy while reducing overall verification time.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system implements two levels of verification: a quick scan that checks metadata signatures for all tracks (partial verification), and a full scan that verifies DIF information only for tracks that failed the quick scan (excessive action only where needed). This resolves the contradiction by achieving high verification accuracy without requiring full verification time for all tracks.

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If data verification is performed before role reversal, then data integrity is improved, but the complexity of the replication system increases

Engineering Contradiction:

Improvedata integrityVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system performs preliminary verification actions (quick scan and full scan) before the role reversal event occurs. This allows data integrity to be confirmed in advance, and any discrepancies to be corrected before failover, thereby improving reliability without adding complex real-time verification mechanisms during the critical role reversal moment.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements two levels of verification: a quick scan that checks metadata signatures for all tracks (partial verification), and a full scan that verifies DIF information only for tracks that failed the quick scan (excessive action only where needed). This resolves the contradiction by achieving high verification accuracy without requiring full verification time for all tracks.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS12111735B2Data error identification prior to role reversal on a remote data replication facility

Publication Date: 2024.10.08 DELL PROD LP

AI summary

A data verification process is implemented before performing role reversal on a remote data replication facility to identify data mismatch errors prior to failover or failback on the remote data replication facility. In situations where the role reversal is planned sufficiently far in advance, a full data scan is implemented by comparing the Data Integrity Field (DIF) information of each track of data on the primary storage array with the DIF information of each corresponding track of data on the backup storage array. In situations where the role reversal is more imminent, a quick scan is implemented by comparing metadata signatures for each track of data on the primary storage array with the metadata signatures of each corresponding track of data on the backup storage array. Once any data mismatch errors are identified, the data on the backup storage array can be corrected prior to role reversal.