Snapshot Capacity Estimation via Logical Space Sampling

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Solution Overview

Problem

There is a need for a simple and improved technique to estimate the amount of space that can be reclaimed by deleting snapshots of different hierarchies of a filesystem at various times without actually deleting the snapshots.

Innovation Solution

A storage system and method that estimate snapshot sizes by sampling the logical address space, identifying unique and group physical capacities through snapshot deletion queries, and attributing space reclamation to specific or groups of snapshots based on data sharing and overwrite timelines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If snapshots are deleted to reclaim space, then storage capacity is freed, but the ability to restore previous filesystem states is lost

Engineering Contradiction:

Improvestorage capacityVSAvoidfilesystem restoration capability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent creates snapshot copies of filesystem data at specific points in time. These snapshots are copied versions that can be independently managed and deleted without affecting the original filesystem data, enabling space reclamation while preserving restoration capability through the copy mechanism.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The system performs preliminary actions by creating snapshots before potential data loss occurs. These pre-established copies allow for future restoration needs to be met without requiring the original data to be preserved indefinitely, enabling selective deletion of older snapshots.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If all snapshots are retained to ensure data restoration, then filesystem recovery capability is maintained, but storage space is consumed

Engineering Contradiction:

Improvedata restoration capabilityVSAvoidstorage space

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent segments the snapshot data into distinct, manageable units that can be individually evaluated for deletion. Each snapshot is treated as a separate entity with its own space consumption metrics, allowing selective retention of critical snapshots while deleting others to free space.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system changes parameters by evaluating snapshots based on multiple criteria including age, data importance, and space consumption. This multi-parameter approach enables dynamic decisions about which snapshots to retain or delete, optimizing the balance between restoration capability and space usage.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If snapshot capacity is estimated by actual deletion and restoration testing, then accurate measurement is obtained, but system operation is disrupted and time is lost

Engineering Contradiction:

Improvesnapshot capacity measurementVSAvoidsystem operation disruption time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent introduces an intermediary estimation mechanism that calculates snapshot capacity without requiring actual deletion and restoration operations. This intermediary process uses metadata analysis and data structure examination to provide accurate capacity measurements while avoiding system disruption.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system performs preliminary analysis of snapshot data structures and metadata to estimate capacity before any deletion operations occur. This preliminary estimation provides accurate measurements without requiring actual restoration testing, saving time and avoiding operational disruption.

Inventive Principle:

Principle #10Preliminary action

4Measurement precision

If detailed analysis of snapshot data is performed to estimate reclamation space, then accuracy is improved, but computational complexity increases

Engineering Contradiction:

Improvereclamation space estimation accuracyVSAvoidcomputational complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the necessary information from snapshot data structures for capacity estimation, rather than performing complete analysis of all snapshot contents. By extracting key metadata and structural information, the system achieves accurate estimation with reduced computational complexity.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The system performs partial analysis focused on the most impactful data elements for capacity estimation. Rather than completely analyzing all snapshot data, it focuses on critical portions that provide the majority of estimation accuracy, reducing overall computational complexity while maintaining sufficient precision.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS11789900B1Snapshot capacity estimation

Publication Date: 2023.10.17 VAST DATA LTD

AI summary

A method for determining size information related one or more snapshots related to file systems stored in a storage system, the method may include (a) sampling one or more combinations of points in time and logical spaces, the logical spaces are associated with the one or more file systems to provide sampled combinations of sampled portions of file system entities (FSEs) and sampled points in time; (b) searching for relevant snapshots that are relevant to the sampled combinations to provide relevant snapshots at the sampled points in time; and (c) determining physical sizes of the relevant snapshots at the sampled point in time; wherein a number of samples per sampled FSE is indicative of a size of the sampled FSEs.