Multi-Channel Garbage Collection in SSDs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional data storage devices, such as SSDs with NAND flash memory, face efficiency degradation due to the exclusive nature of garbage collection operations, which block access to channels during the process, limiting overall performance.
Innovation Solution
A data storage device and method that distribute garbage collection across multiple channels by selecting a victim block and copying its valid pages to an idle or less-accessed channel, utilizing registers to track channel access counts and usage for optimal distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If garbage collection operation is performed for each channel with exclusive access, then data integrity and completion of garbage collection are ensured, but operational efficiency and overall performance deteriorate due to blocked access during garbage collection
Solution Approach 1:
The invention segments the garbage collection operation by separating the victim block selection (first channel) from the valid page copying destination (second channel). This allows the garbage collection process to span multiple channels, enabling concurrent read/write operations in other channels while maintaining data integrity through controlled copying to a designated destination channel.
Solution Approach 2:
The invention introduces a register as an intermediary component to store information about the channel performing garbage collection and the destination channel for copying valid pages. This intermediary mechanism enables coordination between channels, allowing the system to track and manage multi-channel garbage collection operations without blocking all channels, thus improving operational efficiency while ensuring data integrity.
2Reliability
If exclusive access is granted during garbage collection, then garbage collection completion is guaranteed, but resource utilization and channel accessibility are reduced
Solution Approach 1:
The invention divides the garbage collection process into distinct phases: selecting a victim block in the first channel and copying valid pages to a second channel. This segmentation allows different channels to be active simultaneously - the first channel for victim block identification and the second channel for data copying - thereby maintaining channel accessibility while ensuring garbage collection completion.
Solution Approach 2:
The invention dynamically selects which channels are involved in garbage collection based on the current state of the storage device. By using registers to track active channels and their roles, the system can adaptively manage channel access, allowing some channels to be blocked for garbage collection while others remain accessible for normal operations, thus optimizing resource utilization.
3Reliability
If garbage collection blocks access to a channel, then data safety is maintained, but overall system performance and throughput are degraded
Solution Approach 1:
The invention segments the impact of garbage collection by confining it to specific channels rather than blocking all channels. The first channel is used for victim block selection and the second channel for valid page copying, while other channels can continue normal operations. This segmentation maintains data safety within the affected channels while preserving overall system performance through parallel operations.
Solution Approach 2:
The invention changes the parameter of channel access from exclusive to selective. Instead of blocking all channels during garbage collection, the system selectively blocks only the necessary channels for the current garbage collection operation while allowing other channels to remain accessible. This parameter change maintains data safety through controlled access while improving overall system performance by reducing the blocking footprint.
Data Source
AI summary
A data storage device may include: a data storage unit comprising a plurality of channels each having a plurality of nonvolatile memory devices; and a control unit configured to control a garbage collection operation of selecting a first block included in a first channel as a victim block and copying first data included in the first block into a second block included in a second channel that is selected.