Backup Stream De-duplication Using Extent Mapping

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Solution Overview

Problem

Conventional data de-duplication techniques struggle to recognize and eliminate redundant data files across different storage devices, leading to inefficiencies in de-duplication rates due to varying file locations and lack of boundary recognition in image-based backups.

Innovation Solution

The method involves processing a backup stream to access extent mapping, identifying extent groups, and using this information to optimize de-duplication by locating and removing redundant data files, thereby enhancing the de-duplication rate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If fixed size algorithm based de-duplication technique is used, then data blocks can be processed systematically, but identical files at different locations cannot be recognized

Engineering Contradiction:
Improvesystematic processingVSAvoidfile identification accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent segments the backup stream into fixed-size data blocks and processes them systematically through hash functions. Each data block is independently hashed and compared against the lookup table, enabling efficient systematic processing while maintaining the ability to identify identical content regardless of position.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses hash values as copies of the actual data blocks for comparison purposes. Instead of comparing entire files or relying on location information, it creates hash copies that represent the content essence, allowing identical files at different locations to be recognized through their matching hash values.

Inventive Principle:
Principle #26Copying

2Productivity

If de-duplication techniques utilize file boundaries, then redundant data files can be removed, but image-based backups cannot determine data file boundaries

Engineering Contradiction:
Improveredundant data removalVSAvoidfile boundary detection
Core Design Contradiction:
ProductivityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent extracts the essential identifying feature (hash value) from each data block without requiring file boundary information. By taking out the content signature rather than relying on structural boundaries, it enables redundant data removal even in image-based backups where file boundaries are indeterminate.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the parameter used for identification from location-based (file boundaries) to content-based (hash values). This parameter transformation allows the system to work effectively with image-based backups where traditional file boundary detection is not applicable.

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If conventional de-duplication techniques are used, then storage space can be optimized, but de-duplication rate is reduced due to varying file locations

Engineering Contradiction:
Improvestorage space optimizationVSAvoidde-duplication rate
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

The patent creates a universal hash-based identification system that works across all data blocks regardless of their source location or file boundary context. This multi-functional approach allows the same hash comparison mechanism to effectively identify duplicates whether they come from identical files at different locations or from image-based backups without clear boundaries.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentUS8315985B1Optimizing the de-duplication rate for a backup stream
Publication Date: 2012.11.20 COHESITY INC
  • US8315985B1 patent drawing
  • US8315985B1 patent drawing
  • US8315985B1 patent drawing

AI summary

A method and apparatus for optimizing a de-duplication rate for backup streams is described. In one embodiment, the method for optimizing data de-duplication using an extent mapping of a backup stream includes processing a backup stream to access an extent mapping associated with a plurality of data files, wherein the plurality of the data files are arranged within the backup stream and examining the extent mapping to identify at least one extent group within the backup stream, wherein the plurality of the data files are de-duplicated using at least one location of the at least one extent group.