RDM Disk Backup via Mediator Snapshot Replication

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Solution Overview

Problem

Traditional virtual machine backup methodologies do not support the creation of snapshots for virtual machines reliant on raw device mapping (RDM) disks, limiting data backup capabilities for RDM disk-based virtual machines.

Innovation Solution

A method and system that enable data backups for virtual machines using replica RDM disks, allowing for the backup of state and data without disturbing day-to-day operations, by replicating virtual machine snapshots to a remote site and utilizing a MEDITECH backup system for storage and disaster recovery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional virtual machine snapshot approach is used, then backup capability is improved, but compatibility with RDM disk-based virtual machines deteriorates (backup support is lost)

Engineering Contradiction:
Improvebackup capabilityVSAvoidRDM disk compatibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces a mediator component that intercepts I/O operations between the RDM disk-based virtual machine and the physical storage. This mediator captures write operations and redirects them to a backup storage location, enabling backup functionality without requiring changes to the RDM disk architecture itself. The mediator acts as an intermediary layer that preserves RDM compatibility while adding snapshot capabilities.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The backup system is segmented into separate functional components: the original RDM disk path for production operations, a backup path for snapshot operations, and a mediation layer that routes operations appropriately. This segmentation allows the system to maintain native RDM performance for production workloads while enabling backup operations through a separate, dedicated pathway.

Inventive Principle:
Principle #1Segmentation

2Reliability

If snapshot replication is implemented for RDM disks, then data backup reliability is improved, but system complexity increases

Engineering Contradiction:
Improvedata backup reliabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The backup system utilizes the existing replication capabilities already present in the storage infrastructure to perform snapshot operations. Rather than implementing a complex custom replication mechanism, the system leverages self-service features of the underlying storage system, allowing snapshots to be created and replicated using native storage functions that automatically handle the complexity of data copying and consistency management.

Inventive Principle:
Principle #25Self-service

3Reliability

If RDM disk operations are interrupted for backup, then backup completeness is improved, but operational continuity deteriorates

Engineering Contradiction:
Improvebackup completenessVSAvoidoperational continuity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system performs preliminary actions by continuously monitoring and capturing write operations in advance of any potential backup needs. Write operations are intercepted and staged in a buffer or log structure before being committed to the backup storage, ensuring that backup data is already prepared and consistent without requiring interruption of production I/O operations when the backup is initiated.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3570165B1Method and system for enabling data backups for virtual machines reliant on raw device mapping disks
Publication Date: 2022.03.09 EMC IP HLDG CO LLC
  • EP3570165B1 patent drawingFigure 1
  • EP3570165B1 patent drawingFigure 2A
  • EP3570165B1 patent drawingFigure 2B

AI summary

A method and system for enabling data backups for virtual machines reliant on raw data mapping (RDM) disks to store their state and/or data. Traditional virtual machine backup methodologies pivot on the generation and storage of virtual machine snapshots as copies of a virtual machine disk file, which store the state and/or data of a virtual machine at various given points in time. However, these traditional virtual machine backup methodologies, at least at present, do not support the generation and storage of virtual machine snapshots for virtual machines that particularly access and consolidate information on RDM disks. Accordingly, the method and system disclosed herein facilitate the backup of state and/or data pertaining to virtual machines reliant on RDM disks.