SSD Wear Leveling Through Controller-Managed Zone Mapping
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Solution Overview
Problem
Existing wear leveling methods in solid-state drives (SSDs) require the host drive unit to manage and track the program/erase cycles of each zone, increasing its computational burden and affecting system performance.
Innovation Solution
A wear leveling method where the SSD controller determines the zone with the fewest programmed/erased cycles using a mapping relationship, reducing the need for the host drive unit to track these cycles, and uses a mapping table to manage data allocation and migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the host drive unit manages and tracks the program/erase cycles of each zone, then the wear leveling can be implemented, but the computational burden on the host drive unit increases
Solution Approach 1:
The SSD controller autonomously manages wear leveling by automatically tracking program/erase cycles of each zone and selecting zones with fewest cycles for data writing, eliminating the need for the host drive unit to perform these tracking and selection operations, thus reducing host computational burden while maintaining reliable wear leveling
Solution Approach 2:
The SSD controller acts as an intermediary between the host drive unit and the storage zones, handling the complex tasks of cycle tracking and zone selection internally, and only providing simplified interface to the host through zone opening commands and mapping relationships
2Productivity
If the SSD reports residual program/erase cycles of each zone to the host drive unit every time it is powered on, then the host can select zones with more residual cycles, but the communication overhead and processing time increase
Solution Approach 1:
The SSD controller performs preliminary action by pre-tracking and pre-managing the program/erase cycles of all zones internally, so that when the host issues a write command, the controller already has the information needed to select the optimal zone without requiring time-consuming reporting and processing during power-on
3Reliability
If the host drive unit determines the zone with fewest programmed/erased cycles for data writing, then wear leveling is achieved, but the host needs to track cycle information which increases system complexity
Solution Approach 1:
The SSD controller serves itself by internally maintaining track of program/erase cycles for all zones and automatically selecting zones with fewest cycles for data writing operations, eliminating the need for the host drive unit to implement complex cycle tracking mechanisms while achieving reliable wear leveling
Data Source
AI summary
Provided are a solid-state drive and a wear leveling method. The solid-state drive includes a plurality of zones, a mapping relationship and an SSD controller. The SSD controller is configured to: determine, according to the mapping relationship, an identifier of a first target zone corresponding to an identifier of a to-be-written zone in response to receiving a data write command from a host drive unit, and write the to-be-written data to the first target zone. The data write command carries the identifier of the to-be-written zone determined by the host drive unit and to-be-written data, the mapping relationship includes an identifier of an alternate zone corresponding to an identifier of each of the plurality of zones, and the alternate zone of each zone is a zone, determined from the plurality of zones, with fewest programmed/erased cycles.