Multi-Meta-Die Data Routing for Low-Relocation Wear Levelling
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Solution Overview
Problem
In multi-meta-die data storage devices, only a subset of memory dies can operate in parallel due to power and thermal limitations, leading to uneven program-erase cycles and the need for costly and performance-hindering inter-meta-die active wear leveling.
Innovation Solution
A data storage device and method that selects a meta-die for writing data based on the average number of program-erase cycles and relocation effort, minimizing data relocation and optimizing wear leveling by intelligent routing of host writes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of memory dies is increased to achieve higher storage capacity, then storage capacity is improved, but power consumption and thermal issues worsen, limiting the number of dies that can operate in parallel
Solution Approach 1:
The patent divides the storage system into multiple meta-dies, where each meta-die contains multiple memory dies. This segmentation allows the system to manage power consumption at the meta-die level by selectively activating only the required number of meta-dies based on workload demands, thus maintaining high storage capacity while controlling power usage.
2Speed
If more memory dies operate in parallel to improve performance, then processing speed is improved, but thermal generation increases, causing thermal limitations
Solution Approach 1:
The patent implements dynamic meta-die activation where the system can dynamically select and activate only the necessary number of meta-dies based on real-time workload requirements. This dynamic approach allows the system to optimize processing speed by activating more meta-dies when needed while reducing thermal generation by activating fewer meta-dies when workload is light, thus adapting to thermal conditions.
3Reliability
If inter-meta-die active wear leveling is implemented to evenly distribute program-erase cycles, then device reliability is improved, but performance deteriorates due to data relocation overhead
Solution Approach 1:
The patent implements wear leveling primarily within each meta-die rather than across all meta-dies. By focusing wear leveling operations locally within meta-die boundaries, the system achieves reliable wear distribution without the performance penalty of moving data between meta-dies, thus maintaining high productivity while ensuring device reliability.
4Stability of the object's composition
If data is written to the meta-die with the lowest program-erase cycles to balance wear, then wear distribution is improved, but the complexity of managing data routing increases
Solution Approach 1:
The patent pre-calculates and maintains wear level information for each meta-die, allowing the controller to make simple routing decisions based on pre-computed wear metrics. This preliminary preparation of wear information simplifies the data routing logic during write operations, reducing the operational complexity while maintaining good wear distribution.
Data Source
AI summary
A multi-meta-die data storage device disclosed herein routes host writes in such a way to prevent the need for inter-meta-die active wear leveling. In making the meta-die selection, a controller of the data storage device can consider both the average number of program-erase cycles (PEC) of the meta-die, as well as a parameter that indicates the effort required to relocate data from the meta-die to another meta-die. The controller can use this information to normalize PEC among the meta-dies and select the meta-die with the lowest final relocation effort for opening a new block for host writes. This can minimize relocations from active wear leveling.