SSD Controller Wear-Aware Block Segmentation
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Solution Overview
Problem
Current solid-state drive (SSD) systems based on NAND flash technology face challenges in optimizing performance due to inefficient data management and wear leveling, leading to increased write amplification and reduced lifespan, as they lack effective mechanisms for dynamically adjusting data storage based on estimated lifetimes and wear levels of blocks.
Innovation Solution
A memory system with a controller that allocates write data to blocks based on estimated lifetimes, notifies the host of valid data blocks exceeding storage periods, and transfers data to blocks with longer estimated lifetimes, thereby reducing write amplification and extending SSD lifespan by optimizing data placement and wear leveling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If data is written to any available block without considering lifetime information, then write speed is improved, but write amplification increases and SSD lifespan decreases
Solution Approach 1:
The patent segments the memory system into multiple block groups (first block group for short lifetime data, second block group for long lifetime data) and segments write commands into different categories based on lifetime information. This segmentation allows the controller to direct different types of data to appropriate block groups, reducing unnecessary writes and improving write efficiency while extending SSD lifespan.
Solution Approach 2:
The patent applies local quality by treating different block groups with different characteristics - the first block group is optimized for short lifetime data with faster wear, while the second block group is optimized for long lifetime data with slower wear. This localized optimization ensures that each block group handles data appropriate to its characteristics, reducing write amplification and extending overall SSD lifespan.
2Speed
If data is written to any available block without considering lifetime information, then write speed is improved, but SSD lifespan decreases
Solution Approach 1:
The patent segments the memory system into multiple block groups (first block group for short lifetime data, second block group for long lifetime data) and segments write commands into different categories based on lifetime information. This segmentation allows the controller to direct different types of data to appropriate block groups, reducing unnecessary writes and improving write efficiency while extending SSD lifespan.
Solution Approach 2:
The patent applies local quality by treating different block groups with different characteristics - the first block group is optimized for short lifetime data with faster wear, while the second block group is optimized for long lifetime data with slower wear. This localized optimization ensures that each block group handles data appropriate to its characteristics, reducing write amplification and extending overall SSD lifespan.
3Device complexity
If the controller manages all blocks uniformly without lifetime awareness, then device complexity is reduced, but performance optimization is lost
Solution Approach 1:
The patent implements dynamic block group management where the controller can adaptively allocate blocks to different block groups based on lifetime information from write commands. The system dynamically adjusts which block group receives which data, and can migrate data between block groups as needed, providing performance optimization without excessive complexity through rule-based dynamic management.
Solution Approach 2:
The patent changes the parameter of block allocation by introducing lifetime information as a new dimension for data classification. Instead of uniform allocation, the system uses lifetime parameters to determine block group assignment, enabling performance optimization while maintaining manageable complexity through parameter-based routing rules.
Data Source
AI summary
According to one embodiment, a memory system detects a first block in which an elapsed time from a time point at which the block has been filled with write data exceeds a first period. The memory system notifies a host of a list of identifiers capable of identifying valid data portions stored in the first block or a list of identifiers capable of identifying all data portions stored in the first block. When receiving, from the host, a first copy request specifying one or more valid data portions stored in the first block as copy target data and specifying the second block group as a copy destination block group, the memory system copies the one or more valid data portions specified as the copy target data from the first block to the second block group.