Solid-State Storage Wear Tracking for Remaining Life Prediction

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current solid-state storage systems lack a reliable method to predict when non-volatile storage components will exceed their guaranteed endurance, leading to unscheduled downtime and potential data loss due to the inability to monitor and report their remaining useful life effectively.

Innovation Solution

A solid-state storage subsystem that maintains usage statistics reflective of its wear state, allowing a host system to read and report the remaining useful life, enabling informed decision-making on data storage and maintenance schedules through vendor-specific commands and graphical displays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If solid-state storage subsystems operate beyond the specified endurance, then productivity is improved by continuous operation, but reliability deteriorates due to failure risk

Engineering Contradiction:
Improvecontinuous operationVSAvoidfailure risk
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements preliminary action by maintaining usage statistics and predicting remaining useful life before actual failure occurs. The controller continuously monitors program/erase cycle counts and compares them against endurance specifications, enabling the system to take preventive measures (such as warning the host system or migrating data) before the storage device fails, thus maintaining productivity while preventing reliability deterioration.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by creating a closed-loop monitoring system where usage statistics are continuously collected, analyzed, and reported back to the host system. The controller provides real-time feedback on remaining useful life estimates, allowing the host system to adjust its operations accordingly. This feedback mechanism enables proactive management of storage resources, preventing failures while maximizing productive usage.

Inventive Principle:
Principle #23Feedback

2Reliability

If usage statistics are maintained to predict remaining life, then reliability is improved by enabling proactive management, but device complexity increases due to additional monitoring functions

Engineering Contradiction:
Improveproactive managementVSAvoidmonitoring functions
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by designing the controller to perform multiple functions: it simultaneously manages data storage operations and maintains usage statistics for reliability monitoring. The same controller hardware that executes read/write operations also counts program/erase cycles and generates remaining useful life predictions. This multi-functionality approach enables proactive management without adding separate dedicated monitoring hardware, thus limiting the increase in device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent implements self-service by enabling the storage subsystem to autonomously monitor its own health status and provide reliability information. The controller automatically tracks usage statistics, compares them against endurance specifications, and generates predictions without requiring external monitoring equipment. This self-service capability improves reliability through proactive management while minimizing additional device complexity by utilizing the existing controller resources.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If usage statistics are maintained internally, then measurement precision is improved by tracking actual wear, but loss of information occurs in non-user-data areas used for statistics storage

Engineering Contradiction:
Improvewear tracking accuracyVSAvoidnon-user-data area capacity
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent applies the taking out principle by extracting the usage statistics storage function from the main user-data storage area. The controller maintains usage statistics in dedicated non-user-data areas or metadata regions that are separate from user-accessible storage space. This extraction allows precise tracking of wear information without consuming valuable user-data capacity, as the statistics are stored in previously unused or reserved areas of the storage device.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP2021852B1Systems and methods for measuring the useful life of solid-state storage devices
Publication Date: 2016.04.27 WESTERN DIGITAL TECHNOLOGIES INC
  • EP2021852B1 patent drawingFigure 1
  • EP2021852B1 patent drawingFigure 2A~2B
  • EP2021852B1 patent drawingFigure 3

AI summary

A non-volatile solid-state storage subsystem (112), such as a non-volatile memory device, maintains usage statistics (408, 410, 412) reflective of the wear state, and thus the remaining useful life, of the subsystem's memory array (116). A host system (110) reads the usage statistics information, or data derived therefrom, from the subsystem (112) to evaluate the subsystem's remaining life expectancy. The host system (110) may use this information for various purposes, such as to (a) display or report information regarding the remaining life of the subsystem; (b) adjust the frequency with which data is written to the subsystem; and/or (c) select the type(s) of data written to the subsystem.