Stream-Aware Block Allocation for Lower-WAF Flash Storage
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Solution Overview
Problem
Existing storage devices with nonvolatile memory face challenges in managing and controlling operations to achieve lower total cost of ownership (TCO) and higher quality-of-service (QoS), particularly in managing data streams and namespaces, leading to inefficiencies in resource utilization and performance.
Innovation Solution
The storage device employs advanced features such as multi-stream/namespaces control, advanced garbage collection, block boundary reporting, and effective 'hand-shake' garbage collection to optimize resource allocation and management, ensuring efficient data handling and performance across multiple streams and namespaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If advanced multi-stream/namespace control and garbage collection features are implemented, then resource utilization and data handling efficiency are improved, but device complexity increases
Solution Approach 1:
The storage device is divided into multiple independent streams and namespaces, each capable of being managed separately. This segmentation allows parallel processing of different data streams, improving overall productivity while maintaining manageable complexity through modular organization. Each stream can be independently allocated to different physical blocks, enabling fine-grained resource management.
Solution Approach 2:
The controller performs preliminary actions by proactively managing garbage collection and block allocation before resources are fully consumed. The hand-shake garbage collection mechanism anticipates future write operations and prepares blocks in advance, improving data handling efficiency by avoiding last-minute resource conflicts and reducing write amplification.
2Loss of energy
If block boundary alignment and fragmentation reduction techniques are employed, then write amplification factor is reduced, but control overhead increases
Solution Approach 1:
The controller implements a feedback mechanism through block boundary reporting, where the host device receives information about available block boundaries and adjusts its write operations accordingly. This feedback loop enables the system to maintain proper block alignment without excessive control overhead, as the host actively participates in maintaining optimal write patterns based on real-time information from the storage device.
Solution Approach 2:
The block management mechanism serves multiple functions simultaneously: it aligns data to block boundaries, reduces fragmentation, tracks resource allocation across streams, and provides boundary information to the host. This multi-functionality reduces the need for separate control mechanisms, thereby limiting the increase in device complexity while achieving multiple goals.
3Reliability
If resource allocation is optimized across multiple streams, then quality-of-service is improved, but management complexity increases
Solution Approach 1:
The resource allocation system is designed to be dynamic, allowing the controller to adjust block assignments and garbage collection priorities based on real-time stream performance and resource availability. This dynamic adaptation enables the system to maintain high quality-of-service for different streams without requiring complex static allocation schemes, as the system automatically responds to changing conditions.
Data Source
AI summary
A storage device includes a nonvolatile semiconductor memory device including a plurality of physical blocks and a memory controller. The memory controller is configured to associate one or more physical blocks to each of a plurality of stream IDs, execute a first command containing a first stream ID received from a host, by storing write data included in the write IO in the one or more physical blocks associated with the first stream ID, and execute a second command containing a second stream ID received from the host, by selecting a first physical block that includes valid data and invalid data, transfer the valid data stored in the first physical block to a second physical block, and associate the first physical block from which the valid data has been transferred, with the second stream ID.