Virtual Disk Identifier Mismatch Detection

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Solution Overview

Problem

In storage virtualization, the challenge lies in detecting corruption of virtual disks when modifications are made to parent virtual disk files, which can render dependent virtual disks unusable due to changes in identifiers and sector bitmaps, leading to potential data inconsistencies and system instability.

Innovation Solution

Assigning unique identifiers to virtual disk files and their dependent files, and using normalized bitmaps to reflect sector bitmaps accurately, with mechanisms to update these identifiers and bitmaps upon modifications, ensuring data integrity and corruption detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a parent virtual disk file is modified, then the virtual disk functionality is improved or updated, but the identifier in the parent file changes causing mismatch with dependent child files leading to corruption

Engineering Contradiction:

Improvevirtual disk modification capabilityVSAvoiddata consistency between parent and child virtual disk files

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system performs preliminary actions by creating and storing copies of identifiers from parent virtual disk files into child virtual disk files at the time of chain creation. This preliminary capture of identifier states enables later verification without requiring real-time synchronization during modifications.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback mechanisms by comparing identifiers stored in child virtual disk files against current identifiers in parent files during virtual disk instantiation. This feedback loop detects modifications and prevents corruption by identifying mismatches between parent and child file states.

Inventive Principle:

Principle #23Feedback

2Reliability

If identifier checking is implemented to detect corruption, then data integrity is improved, but the complexity of virtual disk file handling increases

Engineering Contradiction:

Improvevirtual disk corruption detectionVSAvoidvirtual disk file management complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system uses copying by storing identifier values from parent virtual disk files into child virtual disk files. These copied identifiers serve as verification tokens that can be compared later without requiring complex real-time validation mechanisms or additional computational resources during normal operations.

Inventive Principle:

Principle #26Copying

3Measurement precision

If normalized bitmaps are persisted for sector tracking, then sector bitmap accuracy is improved, but storage space and processing overhead increase

Engineering Contradiction:

Improvesector bitmap reflection accuracyVSAvoidstorage space for bitmap data

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The system performs preliminary computation of normalized bitmaps that aggregate sector information from multiple virtual disk extents. By pre-computing and persisting these normalized representations, the system avoids redundant real-time computation during virtual disk operations while maintaining accurate sector tracking information.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP2702493B1Virtual disk storage techniques

Publication Date: 2018.08.22 MICROSOFT TECHNOLOGY LICENSING LLC

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AI summary

In an exemplary embodiment, a virtual disk file can be assigned an identifier and a virtual disk files that is dependent on the virtual disk file can include a copy of the identifier. In the instance that the virtual disk file is opened and data is modified that causes the contents of a virtual disk extent to change the identifier can be changed. If the virtual disk file and the dependent virtual disk file are used to instantiate a virtual disk the difference between identifiers can be detected, which is indicative of the fact that the virtual disk may be corrupted. Other techniques are described in the detailed description, claims, and figures that form a part of this document.