Partitioned Nonvolatile Write Buffer for Lower NAND Write Amplification
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
NAND-based storage devices suffer from high write amplification factor (WAF) and read tail latency issues due to inefficient data organization and frequent write operations, which reduce device lifetime and increase power consumption, especially in applications requiring low and stable read latency.
Innovation Solution
Implementing a partitioned write buffer that classifies write requests based on data classification, such as lifetime or velocity, and aggregates data into separate partitions equal to the size of an erase unit before flushing to NAND storage, reducing WAF and improving QoS without requiring application awareness of media characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If data is scattered throughout NAND storage device and written as soon as changes occur, then write operations are simple and fast, but write amplification factor increases and device lifetime decreases
Solution Approach 1:
The patent segments the write buffer into multiple partitions (first write buffer partition and second write buffer partition) that correspond to different erase units in the NAND storage device. This segmentation allows independent management of write operations for different data blocks, enabling the system to batch writes at the erase unit level rather than writing immediately for each change, thereby reducing write amplification and extending device lifetime while maintaining write performance.
2Quantity of substance
If data is scattered throughout NAND storage device, then storage capacity is maximized, but read tail latency increases due to background operations
Solution Approach 1:
The patent divides the storage device into multiple erase units with corresponding write buffer partitions, allowing background operations (erase, wear leveling, garbage collection) to be performed independently on specific erase units without affecting other units. This segmentation isolates background operations from foreground read operations, reducing read tail latency while maintaining full storage capacity utilization.
Solution Approach 2:
The patent introduces a write buffer with multiple partitions as an intermediary layer between the host and the NAND storage device. This intermediary buffers write operations and manages them at the erase unit level, decoupling the host's write requests from the actual NAND write/erase operations. This allows background operations to proceed without directly impacting read latency, as the buffer absorbs and manages the complexity of NAND management operations.
3Device complexity
If traditional NAND write operations are used without partitioning, then device complexity is low, but write amplification factor is high and power consumption increases
Solution Approach 1:
The patent implements a segmented write buffer structure divided into multiple partitions corresponding to different erase units. This segmentation enables the system to batch and consolidate write operations at the erase unit level, reducing the total number of program and erase operations required. By managing writes at the partition level rather than individual block level, the system reduces write amplification factor and associated power consumption while adding only moderate structural complexity.
Data Source
AI summary
A storage system includes a NAND storage media and a nonvolatile storage media as a write buffer for the NAND storage media. The write buffer is partitioned, where the partitions are to buffer write data based on a classification of a received write request. Write requests are placed in the write buffer partition with other write requests of the same classification. The partitions have a size at least equal to the size of an erase unit of the NAND storage media. The write buffer flushes a partition once it has an amount of write data equal to the size of the erase unit.