SSD Write Stream Synchronization to Reduce Amplification

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Managing multiple sequential write streams to a solid state drive (SSD) leads to increased write amplification due to varying wrap-around times, resulting in higher garbage collection needs and reduced write performance, especially when random writes occur, which can degrade SSD endurance.

Innovation Solution

Implementing a method to monitor and match the separate write rates and wrap-around times of multiple sequential write streams, allowing for load balancing and throttling to synchronize their write rates, thereby reducing excessive write amplification by ensuring all streams wrap around simultaneously, thus minimizing garbage collection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple sequential write streams are merged without synchronization, then write throughput increases, but write amplification increases due to mismatched wrap-around times

Engineering Contradiction:

Improvewrite throughputVSAvoidwrite amplification

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The system dynamically adjusts the write rate of individual sequential write streams based on monitored wrap-around times. By making the write rate adaptive rather than fixed, the system ensures that multiple streams synchronize their wrap-around events, preventing partial block invalidation and reducing garbage collection needs while maintaining high write throughput.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system monitors the wrap-around times of multiple sequential write streams and uses this feedback information to adjust write rates. This closed-loop control ensures that streams are synchronized to wrap around simultaneously, eliminating the write amplification problem caused by unsynchronized merges while preserving the throughput benefits of multiple streams.

Inventive Principle:

Principle #23Feedback

2Productivity

If write rates of multiple sequential streams are unsynchronized, then garbage collection frequency increases, but system complexity increases

Engineering Contradiction:

Improvegarbage collection efficiencyVSAvoidwrite rate management complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The system implements self-service by having the storage device automatically monitor its own wrap-around times and adjust write rates without external intervention. This autonomous operation reduces the complexity burden on the host system while maintaining efficient garbage collection through synchronized stream wrapping.

Inventive Principle:

Principle #25Self-service

3Adaptability or versatility

If random writes occur in multi-stream scenarios, then wrap-around synchronization becomes difficult, but write amplification worsens significantly

Engineering Contradiction:

Improvewrite pattern flexibilityVSAvoidwrite amplification

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The system dynamically adapts write rates for different stream types (sequential and random) based on real-time monitoring of wrap-around behavior. This dynamic adjustment allows the system to handle mixed workloads with high flexibility while maintaining synchronization to prevent excessive write amplification.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentEP3230872B1Techniques to manage multiple sequential write streams

Publication Date: 2019.10.23 INTEL CORP

Figure 1
Figure 2
Figure 3

AI summary

Examples may include techniques to manage multiple sequential write streams to a solid state drive (SSD). Wrap around times for each sequential write stream may be determined. Respective wrap around times for each sequential write stream may be changed for at least some of the sequential write streams to cause the multiple sequential write streams to have matching wrap around times.