SSD Controller Feedback for Stream Write Policy Adjustment

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Solution Overview

Problem

Current solid-state drive (SSD) systems face inefficiencies in garbage collection operations due to improper stream write policies, leading to increased frequency of garbage collection, reduced performance, and shortened lifespan, as data with different lifetimes are often allocated to the same stream, resulting in partial invalidation and subsequent garbage collection of erase blocks.

Innovation Solution

The SSD system provides feedback information to the host on the effectiveness of stream write operations, allowing for policy adjustments to prevent ineffective stream write requests, thereby ensuring that only data with similar lifetimes are written to the same erase block, reducing garbage collection frequency and optimizing resource utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If data with different lifetimes are allocated to the same stream, then stream write operations can be simplified, but garbage collection frequency increases and performance deteriorates

Engineering Contradiction:

Improvestream write operation simplicityVSAvoidSSD performance

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The controller monitors garbage collection operations and identifies when they are triggered by ineffective stream write requests. It provides feedback information to the host indicating which stream IDs caused unnecessary garbage collection, allowing the host to adjust its stream allocation policy and avoid allocating data with different lifetimes to the same stream in the future.

Inventive Principle:

Principle #23Feedback

2Speed

If stream write operations are performed without validation, then write speed increases, but unnecessary garbage collection operations occur

Engineering Contradiction:

Improvewrite speedVSAvoidgarbage collection time

Core Design Contradiction:

SpeedVSLoss of time

Solution Approach 1:

The host performs preliminary validation by allocating stream IDs based on data lifetime characteristics before writing data. The controller validates stream write requests by checking whether the allocated stream ID is appropriate for the data lifetime, preventing unnecessary garbage collection operations before they occur.

Inventive Principle:

Principle #10Preliminary action

3Quantity of substance

If erase blocks are frequently reused through garbage collection, then storage capacity is maintained, but device lifespan is shortened

Engineering Contradiction:

Improvestorage capacityVSAvoiddevice lifespan

Core Design Contradiction:

Quantity of substanceVSDuration of action of stationary object

Solution Approach 1:

The controller provides feedback information to the host about ineffective stream write operations that trigger unnecessary garbage collection. The host uses this feedback to improve its stream allocation policy, reducing the frequency of garbage collection operations and thereby extending the device lifespan while maintaining storage capacity.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS10191688B2Memory system and information processing system

Publication Date: 2019.01.29 KIOXIA CORP

AI summary

According to one embodiment, a memory system includes a nonvolatile memory and a controller. The nonvolatile memory includes erase blocks. The controller is configured to provide a host device with first information. The first information is indicative of whether or not an erase block to which data associated with a first stream are written and data unassociated with the first stream are not written is used for a garbage collection operation of the nonvolatile memory.