Sequential Storage Image Block Reordering for Granular Restoration

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Solution Overview

Problem

Existing data backup systems face inefficiencies in granular restoration from sequential storage due to fragmentation, requiring a full scan of the storage device to locate scattered file blocks, making the process time-consuming and inefficient.

Innovation Solution

Generating a re-ordered block layout for each file based on file extents to make blocks contiguous, along with layout metadata, and storing this layout to sequential storage, allowing for efficient granular and full restoration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If data image is streamed in original format to sequential storage, then backup process is simple, but file blocks become fragmented and granular restoration becomes inefficient

Engineering Contradiction:

Improvebackup process simplicityVSAvoidgranular restoration efficiency

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent applies preliminary action by re-ordering file blocks to be contiguous during the backup process itself, rather than during restoration. The backup system performs block re-ordering and generates layout metadata upfront, so that when granular restoration is needed, files can be directly accessed without scanning. This preliminary organization of data blocks resolves the fragmentation issue before it affects restoration efficiency.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent segments the backup process into distinct phases: (1) capturing data image, (2) re-ordering blocks by file extent to create contiguous layouts, (3) generating layout metadata that maps original and re-ordered block positions, and (4) streaming to sequential storage. This segmentation allows the system to maintain simplicity in the overall backup workflow while inserting the block re-ordering operation to improve future restoration efficiency.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If file blocks are scattered on sequential storage, then storage space utilization is flexible, but locating blocks for granular restoration requires full scan of storage device

Engineering Contradiction:

Improvestorage space utilization flexibilityVSAvoidtime to locate file blocks

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent introduces layout metadata as an intermediary between the stored data blocks and the restoration process. This metadata contains information about the re-ordered block positions and file extent mappings, allowing the restoration system to directly locate file blocks without scanning the entire sequential storage device. The metadata acts as an index that bridges the gap between contiguous block storage and efficient file retrieval.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system performs preliminary organization of blocks into contiguous layouts during backup and pre-generates the layout metadata that will enable fast block location during restoration. This preliminary action eliminates the need for time-consuming full scans during granular restoration operations.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If blocks are re-ordered to be contiguous for each file, then granular restoration efficiency improves, but backup process complexity increases

Engineering Contradiction:

Improvegranular restoration speedVSAvoidbackup process complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent performs the complex block re-ordering operation as a preliminary action during the backup process, when the system has full control over data organization. By re-ordering blocks and generating layout metadata upfront, the system pays the complexity cost once during backup, enabling simple and fast granular restoration operations later without requiring complex scanning or search algorithms.

Inventive Principle:

Principle #10Preliminary action

4Reliability

If entire data image must be restored for granular file recovery, then data integrity is maintained, but restoration time increases significantly

Engineering Contradiction:

Improvedata integrityVSAvoidrestoration time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent extracts the ability to perform selective granular restoration from the requirement to restore entire data images. By organizing blocks contiguously by file and providing layout metadata that maps block positions, the system can extract and restore only the specific file blocks needed, rather than restoring the entire data image. This maintains data integrity while dramatically reducing restoration time for individual file recovery operations.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS8170991B1Method and apparatus for managing image data on a sequential storage device

Publication Date: 2012.05.01 COHESITY INC

AI summary

Method, apparatus, and computer readable medium for managing an image of a storage volume are described. File extents for each of a plurality of files as defined in an original block layout of the image are obtained. A re-ordered block layout is generated by re-ordering, for each file of the plurality of files, blocks as defined by the original block layout based on the file extents of the respective file such that the blocks are contiguous. Layout metadata indicative of a mapping between the original block layout and the re-ordered block layout is generated. An archive image having the re-ordered block layout and the layout metadata is stored to a sequential storage device.