Virtual Volume Snapshot Generation via Storage Array Journaling

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Solution Overview

Problem

Conventional data protection systems face challenges in efficiently generating and accessing virtual volume snapshots, particularly in rolling back data to a specific point in time for disaster recovery or data access purposes.

Innovation Solution

A method and apparatus that receive a request to access a virtual volume snapshot, prepare to bind it, intercept commands, roll back to the corresponding point in time, and generate the snapshot within a storage array, utilizing techniques such as journaling and data replication to maintain data integrity and accessibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional data protection systems use tape backup drives or data replication to create snapshots, then data protection capability is improved, but system complexity and access efficiency deteriorate

Engineering Contradiction:

Improvedata protection capabilityVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a storage array as an intermediary component between the host system and backup storage. The storage array autonomously generates snapshots of virtual volumes using journaling technology, eliminating the need for complex host-level backup software and manual intervention. This intermediary layer handles snapshot creation and management automatically, reducing system complexity while maintaining robust data protection.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements efficient copying mechanisms where the storage array creates point-in-time copies of virtual volumes through journaling. Instead of traditional full backups, the system maintains a journal of changes and generates snapshots by replaying or reverting journal entries. This copying approach enables rapid snapshot creation with minimal impact on production systems.

Inventive Principle:

Principle #26Copying

2Ease of operation

If the system rolls back data to a specific point in time for snapshot generation, then snapshot accessibility is improved, but processing time increases

Engineering Contradiction:

Improvesnapshot accessibilityVSAvoidprocessing time

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

The storage array continuously maintains a journal of all write operations to virtual volumes before snapshots are requested. This preliminary action of pre-capturing all data changes in the journal allows the system to generate snapshots instantly by simply pointing to the appropriate journal checkpoint, rather than performing time-consuming data copying or rollback operations when snapshots are needed.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces traditional mechanical backup operations (physical tape winding, data copying) with a logical journaling system. Instead of physically moving or copying data to create snapshots, the system uses logical pointers to journal entries representing different points in time. This substitution dramatically reduces processing time while maintaining snapshot accessibility.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If the system generates and stores multiple virtual volume snapshots, then data recovery options are improved, but storage space consumption increases

Engineering Contradiction:

Improvedata recovery optionsVSAvoidstorage space consumption

Core Design Contradiction:

Adaptability or versatilityVSVolume of stationary object

Solution Approach 1:

The patent segments the storage of snapshot data by maintaining a separate journal structure that records all changes chronologically. Instead of storing complete duplicate copies of each snapshot, the system segments storage into the original virtual volume and incremental journal entries. This segmentation allows multiple recovery points to be maintained with minimal additional storage space, as each journal entry only stores the specific changes made since the last checkpoint.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The journal structure implements a nested organization where journal entries are organized chronologically with each entry referencing previous states. The system nests multiple snapshot points within a single continuous journal structure, allowing efficient storage of numerous recovery options without proportionally increasing storage consumption. Each snapshot is essentially a reference point within the nested journal hierarchy rather than a complete separate copy.

Inventive Principle:

Principle #7Nested doll (Nesting)

Data Source

PatentUS9223659B1Generating and accessing a virtual volume snapshot in a continuous data protection system

Publication Date: 2015.12.29 EMC INT

AI summary

In one aspect, a method includes receiving a request to access a virtual volume snapshot, preparing to bind the virtual volume snapshot, intercepting a command to prepare bind of the virtual volume snapshot, rolling back to a point in time corresponding to the requested virtual volume snapshot and generating a virtual volume snapshot in a storage array.