Distributed Storage Task Coordination for Failure-Tolerant Maintenance

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Solution Overview

Problem

Current RAID systems face challenges with disk failures leading to data loss, increased maintenance costs, and security issues due to the need for manual replacement and potential unauthorized access, especially in dispersed storage networks where data is geographically distributed.

Innovation Solution

A dispersed storage network (DSN) with a managing unit and integrity processing unit that employs error encoding and decoding using Cauchy Reed-Solomon encoding, allowing for data redundancy without redundant copies, and coordinates maintenance tasks through a layered queue system to minimize data loss and ensure security.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual replacement of failed disks is performed in RAID systems, then data loss can be prevented, but maintenance costs and time increase

Engineering Contradiction:
Improvedata loss preventionVSAvoidmaintenance time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary actions by continuously monitoring disk health metrics and predicting failures before they occur. When a disk is predicted to fail, the system proactively replaces it during low-activity periods, preventing actual failures and data loss while avoiding emergency maintenance operations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback mechanisms by continuously collecting disk performance data, analyzing trends, and adjusting maintenance schedules accordingly. The feedback loop enables dynamic optimization of replacement timing, balancing data protection needs with minimal disruption to system operations.

Inventive Principle:
Principle #23Feedback

2Reliability

If multiple copies of data are stored in RAID systems, then data loss risk is reduced, but security vulnerabilities increase due to unauthorized access

Engineering Contradiction:
Improvedata loss risk reductionVSAvoidunauthorized access risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system segments data into multiple encoded slices distributed across different storage locations. Instead of storing complete redundant copies, the data is divided and encoded such that a threshold number of slices are needed to reconstruct the original data, reducing the security risk associated with complete data copies while maintaining fault tolerance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes the parameter of data representation from identical redundant copies to mathematically transformed encoded slices using erasure coding. This transformation maintains the ability to recover data from a subset of slices while ensuring that individual slices or small groups do not reveal the complete data, thereby improving security.

Inventive Principle:
Principle #35Parameter changes

3Speed

If RAID devices are co-located for efficient access, then response time improves, but vulnerability to complete data loss from disasters increases

Engineering Contradiction:
Improvedata access speedVSAvoiddisaster resistance
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The system segments data slices and distributes them across multiple geographic locations while maintaining organized structure. This segmentation enables the system to tolerate local disasters affecting specific locations, as data can be reconstructed from slices stored at other locations, thereby improving disaster resistance without completely sacrificing access efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system adds a geographic distribution dimension to the storage architecture. By distributing data slices across multiple locations spatially, the system creates redundancy against location-specific disasters while maintaining efficient access patterns through intelligent data placement and retrieval strategies that consider both speed and resilience requirements.

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

4Quantity of substance

If more disks are added to RAID array to increase storage capacity, then data availability improves, but probability of disk failure increases

Engineering Contradiction:
Improvestorage capacityVSAvoiddisk failure probability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The system uses erasure coding to create mathematical copies (encoded slices) of the data that are more efficient than traditional redundant copies. These encoded slices provide the same fault tolerance benefits as redundant copies but with better space efficiency, allowing the system to maintain high reliability even as storage capacity increases and more disks are added to the array.

Inventive Principle:
Principle #26Copying

Data Source

PatentUS11907566B1Coordination of task execution in a distributed storage network
Publication Date: 2024.02.20 PURE STORAGE INC
  • US11907566B1 patent drawing
  • US11907566B1 patent drawing
  • US11907566B1 patent drawing

AI summary

Methods for use in a dispersed storage network (DSN) to coordinate execution of tasks by storage units of the DSN. In an embodiment, a computing device of the DSN receives a task (e.g., a maintenance task) to be performed by at least one storage unit of a plurality of storage units. The computing device determines the availability of processing resources of the storage units for execution of the received task. The computing device further compares the respective availability of the processing resources of the storage units of the plurality of storage units to identify a storage unit for execution of the received task, and allocates the received task to the identified storage. In various embodiments, comparing the respective availability of the processing resources includes predicting an impact, with respect to other storage units of the DSN, of performing the received task on the identified storage unit.