SSD Wear Leveling Using Virtual Block Erase Counts and Hot Data
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Solution Overview
Problem
The service life of solid state drives (SSDs) is limited by the number of times a block can be erased, leading to uneven wear that results in some blocks becoming bad blocks quickly while others remain underutilized, thereby shortening the overall lifespan.
Innovation Solution
Implementing a wear leveling algorithm that balances the erase count of virtual blocks by moving data from heavily used blocks to underutilized ones, using a memory controller to manage data movement based on erase count and hot data identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If data is continuously written to SSD blocks, then storage capacity is utilized, but the service life of the SSD is shortened due to uneven wear and blocks becoming bad blocks
Solution Approach 1:
The patent implements dynamic wear leveling by continuously monitoring erase counts of virtual blocks and adaptively selecting source and target blocks based on current wear states. The memory controller dynamically adjusts data migration operations to balance erase counts across blocks, preventing any single block from reaching its endurance limit while maximizing storage utilization.
Solution Approach 2:
The system employs feedback mechanisms by tracking erase counts of all virtual blocks and using this information to make informed decisions about data migration. The memory controller uses erase count information to identify heavily used blocks as sources and underutilized blocks as targets, creating a closed-loop control system that continuously optimizes wear distribution.
2Reliability
If wear leveling algorithms are implemented to balance erase counts, then service life is extended, but device complexity increases due to additional data movement operations
Solution Approach 1:
The wear leveling system operates autonomously without requiring host intervention. The memory controller automatically monitors erase counts, identifies source and target blocks, and executes data migration operations independently. This self-service approach manages wear balancing internally while presenting a simple interface to the host system.
Solution Approach 2:
The patent divides the storage space into multiple virtual blocks that can be independently managed. By segmenting the storage medium into manageable units with individual erase counters, the system can selectively migrate data between specific blocks rather than managing the entire storage space as a single unit, reducing control complexity.
3Reliability
If data is moved from heavily used blocks to underutilized blocks, then erase count distribution is balanced, but additional write operations are performed increasing write amplification
Solution Approach 1:
The system changes the operational parameters of block management by introducing virtual block abstraction and hot/idle state classification. By modifying how blocks are identified and selected based on erase count parameters and data access patterns, the system performs wear leveling operations that are more efficient and better timed, reducing unnecessary write amplification.
Solution Approach 2:
The patent performs preliminary classification of blocks into hot and idle states based on erase counts before executing data migration. By pre-identifying suitable source and target blocks and preparing the migration operation in advance, the system reduces the total number of write operations needed and minimizes write amplification during the actual wear leveling process.
Data Source
AI summary
The present disclosure provides a method of operating a memory system, a memory controller, a memory system, and a storage medium, and relates to the technical field of semiconductor chips. The method includes: obtaining an erase count and a hot id of each virtual block, determining a first virtual block from which data is moved and a second virtual block into which the data is moved according to the erase count and the hot id of each virtual block, and moving data stored in the first virtual block to the second virtual block. The method of operating a memory system provided by the present disclosure is intended to improve the problem that the service life of a solid state drive is shorten due to the movement of newly-written data.