Flash Registry Write Leveling for NAND Flash Endurance
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Solution Overview
Problem
Conventional data storage methods using NAND flash devices are inefficient due to their limited number of supported writes, as traditional tree-based data structures require frequent updates, exceeding the write capacity of NAND flash media.
Innovation Solution
A data structure that trades writes for reads, utilizing a flash registry with write leveling and caching, and a shadow registry to minimize the number of writes to NAND flash-based storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional tree-based data structures are used for data storage, then data organization and access are simplified, but the number of write operations increases excessively, exceeding the limited write capacity of NAND flash media
Solution Approach 1:
The patent introduces a shadow registry that creates a copy of the registry structure in memory, allowing write operations to be performed on the shadow copy rather than directly on the NAND flash storage. This copy enables frequent updates without consuming write capacity on the physical storage medium, thereby resolving the contradiction between ease of data organization and limited write capacity.
Solution Approach 2:
The patent performs preliminary actions by maintaining a shadow registry in memory that is updated before actual writes to NAND flash occur. Changes are accumulated and batched, then written to flash in larger periodic operations. This preliminary buffering of write operations reduces the frequency of direct writes to flash storage, solving the write capacity limitation while maintaining efficient data organization.
2Stability of the object's composition
If frequent writes are performed to update data structures, then data consistency is maintained, but the limited write endurance of NAND flash devices is exhausted prematurely
Solution Approach 1:
By copying the registry structure into a shadow registry in memory, the system can maintain data consistency through frequent updates on the shadow copy without consuming the write endurance of the physical NAND flash devices. The shadow registry acts as a buffer that preserves data consistency while protecting the flash storage from excessive write operations.
Solution Approach 2:
The patent implements periodic action by accumulating write operations in the shadow registry and then performing batched writes to NAND flash at periodic intervals. This approach maintains data consistency through continuous updates on the shadow structure while reducing the frequency of physical writes to flash storage, thereby extending the write endurance lifespan of the devices.
3Productivity
If a shadow registry is introduced to reduce write operations, then write capacity is conserved, but system complexity increases
Solution Approach 1:
The shadow registry is implemented as a direct copy of the existing registry structure, using the same data organization and access patterns. This copying approach preserves the simplicity of the original tree-based structure while adding the benefit of reduced write operations to flash storage, thereby minimizing the increase in system complexity while improving write capacity utilization.
Data Source
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AI summary
A plurality of computing devices are communicatively coupled to each other via a network, and each of the plurality of computing devices is operably coupled to one or more of a plurality of storage devices. A plurality of failure resilient address spaces are distributed across the plurality of storage devices such that each of the plurality of failure resilient address spaces spans a plurality of the storage devices. Each computing device is operable to maintain a two-level registry that records changes in the memory. When data is read from memory, recent changes to the data may be applied according to one or more corresponding registry blocks. Thus, the two-level registry enables the plurality of computing devices to postpone and/or consolidate writes to memory (e.g., non-volatile flash drives).