SSD Write Amplification Reduction via Separate Logical Erase Blocks
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Solution Overview
Problem
Conventional solid-state drives (SSDs) face high write amplification due to the need for garbage collection and out-of-place writes, which increases the number of write operations and reduces the endurance of NAND flash memory, leading to performance degradation and shorter device lifespan.
Innovation Solution
The solution involves maintaining separate open logical erase blocks for user writes and relocate writes, allowing for active separation of different write operations, thereby reducing the frequency of garbage collection and minimizing the number of write operations required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If separate logical erase blocks are maintained for user writes and relocate writes, then write amplification is reduced and NAND flash memory lifespan is extended, but device complexity increases
Solution Approach 1:
The patent divides the logical erase block into two separate blocks: one dedicated to user writes and another for relocate writes. This segmentation allows independent management of user data and garbage collection operations, reducing write amplification by preventing user writes from interfering with relocate operations, thereby extending NAND flash memory lifespan while maintaining manageable complexity through structured separation
2Productivity
If garbage collection is deferred to maximize invalidated data in block, then the number of valid pages to relocate is reduced, but write amplification increases due to delayed relocation operations
Solution Approach 1:
The patent performs preliminary separation of user writes and relocate writes into different logical erase blocks before garbage collection occurs. This preliminary action ensures that when garbage collection is deferred, only relocate writes need to be moved, not user data, thereby reducing the number of valid pages to relocate and minimizing write amplification while maintaining garbage collection efficiency
3Device complexity
If user writes and relocate writes are mixed in the same logical erase block, then device complexity is reduced, but performance degrades due to increased garbage collection frequency
Solution Approach 1:
The patent segments the logical erase block into separate blocks for user writes and relocate writes. This segmentation improves SSD performance by allowing independent management of user data and garbage collection operations, reducing the frequency of garbage collection interruptions, and enhancing overall productivity despite the increased structural organization required
Data Source
AI summary
A computer program product, according to one embodiment, includes a computer readable storage medium having program instructions embodied therewith. The computer readable storage medium is not a transitory signal per se. Moreover, the program instructions are readable and/or executable by a processor to cause the processor to perform a method which includes: maintaining a first open logical erase block for user writes, and a second open logical erase block for relocate writes. A first data stream having the user writes is received, and transferred to the first open logical erase block. A second data stream having the relocate writes is also received, and transferred to the second open logical erase block. Furthermore, a third data stream is received, and is mixed with the first, second, and/or another data stream in response to determining that an open logical erase block is not available for assignment to the third data stream.