Dispersed Storage Write Threshold Scaling for Failure-Tolerant Performance

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Solution Overview

Problem

Existing data storage systems face challenges in maintaining high performance and reliability due to variability in network operations and potential failures, which prior art does not adequately address.

Innovation Solution

A dispersed storage network (DSN) with error encoding and decoding capabilities, utilizing Cauchy Reed-Solomon encoding, manages data distribution across multiple storage units, allowing for error correction and secure storage without redundant copies, and dynamically adjusts write threshold parameters based on performance and resource utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional RAID or dispersed storage systems are used, then data redundancy and reliability are provided, but performance variability and latency cannot be adequately handled

Engineering Contradiction:
Improvedata reliabilityVSAvoidperformance variability handling
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system dynamically adjusts the write threshold parameter based on real-time conditions such as network performance, storage unit availability, and workload characteristics. This allows the storage system to adapt to changing conditions and maintain optimal performance while ensuring data reliability, resolving the contradiction between fixed reliability mechanisms and dynamic performance requirements.

Inventive Principle:
Principle #15Dynamics

2Reliability

If more encoded data slices are stored beyond the write threshold, then performance and reliability are improved, but storage resource utilization increases

Engineering Contradiction:
Improvesystem reliabilityVSAvoidstorage resource utilization
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The system changes the write threshold parameter dynamically based on operational conditions, network performance, and storage availability. By adjusting this parameter, the system can optimize the balance between storing extra encoded slices for reliability and maintaining efficient storage resource utilization, avoiding both over-provisioning and under-provisioning.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the write threshold is increased for better reliability, then tolerance to storage unit failures improves, but write performance and resource utilization may deteriorate

Engineering Contradiction:
Improvefailure toleranceVSAvoidwrite performance
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The write threshold is adjusted dynamically rather than being fixed. During periods of high availability and good network conditions, the threshold can be increased to improve failure tolerance. During periods of high load or degraded conditions, the threshold is reduced to maintain write performance, thus resolving the contradiction between reliability and productivity.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS10871905B2Extra write scaling for performance and reliability
Publication Date: 2020.12.22 PURE STORAGE INC
  • US10871905B2 patent drawing
  • US10871905B2 patent drawing
  • US10871905B2 patent drawing

AI summary

A computing device includes an interface configured to interface and communicate with a dispersed storage network (DSN), a memory that stores operational instructions, and a processing module operably coupled to the interface and memory such that the processing module, when operable within the computing device based on the operational instructions, is configured to perform various operations. For example, the computing device monitors storage unit (SU)-based write transfer rates and SU-based write failure rates associated with each of the SUs for a write request of encoded data slices (EDSs) to the SUs within the DSN. The computing device generates and maintains a SU write performance distribution based on monitoring of the SU-based write transfer rates and the SU-based write failure rates and adaptively adjusts a trimmed write threshold number of EDSs and/or a target width of EDSs for write requests of sets of EDSs to the SUs within the DSN.