QLC SSD Storage Endurance Through Preemptive Garbage Collection

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Solution Overview

Problem

Quad-level cell (QLC) SSDs have relatively poor durability due to frequent internal refreshes, which reduce their endurance and efficiency.

Innovation Solution

Perform system-level garbage collection on erase blocks just before they are internally refreshed to prevent the need for internal refresh operations, thereby extending SSD storage endurance and improving storage efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If QLC SSDs are used to increase storage capacity and reduce cost, then storage capacity and cost-effectiveness are improved, but durability and endurance deteriorate due to frequent internal refreshes

Engineering Contradiction:

Improvestorage capacityVSAvoiddurability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The system performs garbage collection operations in advance before the internal refresh deadline to clear erase blocks of valid data. This preliminary action prevents the need for subsequent refresh operations, thereby improving endurance while maintaining the use of high-capacity QLC SSDs

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent extracts the harmful refresh operations by removing valid data from erase blocks through garbage collection. By taking out the valid data before refresh, the system eliminates the need for refresh operations that would otherwise consume endurance

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If internal refresh operations are performed frequently to prevent data loss, then data reliability is maintained, but storage endurance and efficiency deteriorate

Engineering Contradiction:

Improvedata reliabilityVSAvoidstorage endurance

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The system performs garbage collection before the refresh deadline to proactively clear erase blocks. This preliminary action ensures data reliability is maintained through alternative means (garbage collection rather than refresh), thereby extending storage endurance

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system applies preliminary anti-action by performing garbage collection to remove valid data before the refresh operation would occur. This counteracts the need for refresh operations that would otherwise consume endurance while maintaining data reliability

Inventive Principle:

Principle #9Preliminary anti-action

3Productivity

If garbage collection is performed to consolidate valid data and free erase blocks, then storage efficiency is improved, but additional write operations increase wear on the SSD

Engineering Contradiction:

Improvestorage efficiencyVSAvoidendurance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system performs garbage collection in advance before the refresh deadline, consolidating valid data and freeing erase blocks. This preliminary garbage collection improves storage efficiency while the timing strategy minimizes additional wear by preventing subsequent refresh operations

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12386738B1Providing endurance to solid state device storage

Publication Date: 2025.08.12 DELL PROD LP

AI summary

A technique is directed to providing endurance to solid state device (SSD) storage. The technique involves storing data in an erase block of the SSD storage. The technique further involves detecting that an internal periodic refresh service operating within the SSD storage is currently configured to perform a refresh operation for the erase block at a target refresh time that is within an upcoming amount of time. The technique further involves, in response to detecting that the internal periodic refresh service is currently configured to perform a refresh operation for the erase block at the target refresh time that is within the upcoming amount of time, performing a system-level garbage collection operation on the data stored in the erase block to prevent the internal periodic refresh service from performing a refresh operation for the erase block at the target refresh time.