Zoned Namespace Storage Controller Memory Block Deallocation
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Solution Overview
Problem
Non-volatile memory devices experience frequent garbage collection operations due to random access patterns, leading to reduced storage capacity and increased wear, as existing storage controllers manage data randomly across the entire memory region rather than in zones, causing inefficiencies in data processing and power consumption.
Innovation Solution
A storage controller with a zoned namespace (ZNS) manager that deallocates memory blocks by loading allocation list information from an allocation list table, mapping sequential physical page numbers to sequential logical page numbers, and providing physical erase requests to the non-volatile memory device, allowing for sequential write operations and reducing garbage collection load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If random access is used to store data in non-volatile memory, then data can be stored flexibly, but frequent garbage collection operations occur causing decreased device lifetime
Solution Approach 1:
The memory space is divided into multiple zones (hot zone, cold zone, archive zone) based on data access patterns. This segmentation allows different garbage collection strategies to be applied to different zones, reducing overall GC frequency and extending device lifetime while maintaining storage flexibility.
Solution Approach 2:
The zone boundaries and data placement are dynamically adjusted based on access patterns. Frequently accessed data remains in hot zones with optimized management, while less accessed data moves to cold or archive zones, adapting the storage structure to usage patterns to minimize GC operations.
2Reliability
If a large over provisioning region is allocated for garbage collection and wear leveling, then data management is improved, but available storage capacity decreases
Solution Approach 1:
The over-provisioning space is segmented and allocated specifically to archive zones for bad block management and wear leveling, rather than requiring a large unified OP region. This allows efficient use of spare capacity while maintaining data management capabilities.
Solution Approach 2:
The garbage collection threshold and frequency are dynamically adjusted based on zone characteristics and wear levels. Archive zones with slower access patterns can tolerate higher GC thresholds, reducing the amount of over-provisioning needed while maintaining reliability.
3Productivity
If sequential write operations are implemented in ZNS, then data processing speed improves, but complex mapping management is required
Solution Approach 1:
The mapping table is segmented by zone, with each zone having its own mapping structures. This allows sequential writes within a zone to be handled efficiently with simpler mapping updates, while reducing overall complexity through localized management rather than global mapping complexity.
Solution Approach 2:
The patent uses a simplified mapping approach for sequential writes that doesn't require complex long-term tracking. Once data is written sequentially to a zone, the mapping can be simplified or discarded for that region, reducing management complexity while maintaining write performance.
Data Source
AI summary
Disclosed is a method of operating a storage controller, the storage controller communicating with a host and a non-volatile memory device. The method includes receiving a first erase request from the host, the first erase request being for a first zone of a plurality of zones of the non-volatile memory device, loading first allocation list information of the first zone from an allocation list table based on the first erase request, deallocating memory blocks allocated to the first zone based on the first allocation list information, wherein sequential physical page numbers of the memory blocks are respectively mapped onto sequential logical page numbers, and providing the non-volatile memory device with a physical erase request for the deallocated memory blocks of the first zone.