Multi-Level Lightweight Snapshots for Rapid Data Restore

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Solution Overview

Problem

Current data restore techniques require frequent backups, leading to excessive storage costs and long restore times due to the need for high-frequency snapshotting, which users find unacceptable as they demand quicker restore times without incurring higher storage expenses.

Innovation Solution

Implementing multiple levels of lightweight snapshots that capture data at varying granularities, allowing for efficient storage and rapid recovery by cascading data from higher to lower levels, reducing the need for extensive storage and processing resources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If frequent backups are taken to reduce restore time, then restore speed is improved, but storage cost increases

Engineering Contradiction:
Improverestore timeVSAvoidstorage space
Core Design Contradiction:
Loss of timeVSQuantity of substance

Solution Approach 1:

The patent divides backup data into multiple hierarchical levels (Level 0 being the most recent, Level 1, Level 2, etc.), where each level contains snapshots at different frequencies. This segmentation allows the system to provide rapid restore capability for recent data while using less frequent backups for historical data, thus reducing overall storage requirements while maintaining fast restore performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system implements periodic snapshots at different frequencies for different levels. Level 0 snapshots are taken most frequently (e.g., every minute), while Level 1, Level 2, and subsequent levels use progressively lower frequencies. This periodic action pattern enables the system to balance restore speed requirements with storage cost constraints.

Inventive Principle:
Principle #19Periodic action

2Measurement precision

If high-frequency snapshots are taken to enable granular restore, then restore granularity is improved, but device complexity increases

Engineering Contradiction:
Improverestore granularityVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the snapshot hierarchy into multiple levels with different granularities. Level 0 provides fine-grained restore capability for recent data, while higher levels provide coarser granularity for historical data. This segmentation allows the system to achieve granular restore without the complexity of maintaining uniformly high-frequency snapshots across all time periods.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system adds a hierarchical dimension to the snapshot structure, organizing snapshots not just by time but by level. This dimensional organization simplifies the complexity by providing a structured approach to managing granular restore capabilities across different time periods and frequency requirements.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS11442647B2Lossless data restore using multiple levels of lightweight snapshots
Publication Date: 2022.09.13 NUTANIX INC
  • US11442647B2 patent drawing
  • US11442647B2 patent drawing
  • US11442647B2 patent drawing

AI summary

Systems for high performance restore of data to storage devices. A method embodiment commences upon identifying a plurality of virtual disks to be grouped together into one or more consistency sets. Storage I/O commands for the plurality of virtual disks of the consistency sets are captured into multiple levels of backup data. On a time schedule, multiple levels of backup data for the virtual disks are cascaded by processing data from one or more higher granularity levels of backup data to one or more lower granularity levels of backup data. A restore operation can access the multiple levels of backup data to construct a restore set that is consistent to a designated point in time or to a designated state. Multiple staging areas can be maintained using lightweight snapshot data structures that each comprise a series of captured I/Os to be replayed over other datasets to generate a restore set.