SSD Controller Write Command Reordering for QLC Buffer Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current solid-state drive (SSD) systems require a large buffer to manage write operations efficiently, especially when dealing with quad-level cell (QLC) blocks, which leads to increased storage needs and potential performance bottlenecks due to the sequential writing requirement across memory cells.
Innovation Solution
The implementation of a memory system with a controller that reorders write commands to ensure sequential writing within zones, allowing for efficient data transfer and storage by utilizing a reorder command buffer, thereby reducing the need for a large buffer and improving write throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large buffer is provided in the SSD to manage write operations, then write operation management is improved, but the size of the buffer increases leading to increased storage needs and potential performance bottlenecks
Solution Approach 1:
The patent segments the write operation management into two parts: the host manages write command ordering in its buffer, while the SSD controller manages only the execution of these commands. This segmentation allows the SSD to use a smaller buffer while maintaining reliable write operation management, as the host承担sthe burden of large buffer management.
Solution Approach 2:
The patent introduces write commands as an intermediary mechanism that carries write data from the host to the SSD. These commands include metadata about data location and ordering information, allowing the host to manage the buffer and command ordering, while the SSD controller focuses on executing commands and managing the actual write operations to memory cells.
2Reliability
If sequential writing is enforced across memory cells in QLC blocks, then data integrity is improved, but write throughput decreases due to the sequential requirement
Solution Approach 1:
The patent implements dynamic write command reordering at the host side, where write commands are arranged in sequential order based on memory cell addresses before being sent to the SSD. This dynamic reordering allows the system to maintain sequential writing requirements for data integrity while enabling parallel processing of multiple sequential command streams, thereby improving overall write throughput.
Solution Approach 2:
The patent performs preliminary sorting and reordering of write commands at the host before transmission to the SSD. By pre-organizing commands in sequential order and including metadata about the desired write sequence, the host prepares the command stream in advance, allowing the SSD controller to execute writes efficiently without needing to perform complex reordering operations that would reduce throughput.
3Ease of operation
If the host does not strictly manage write command order, then ease of operation is improved, but the complexity of managing write operations increases for the SSD controller
Solution Approach 1:
The patent uses write commands with embedded metadata as an intermediary that carries ordering information from the host to the SSD controller. The host simply issues write commands with basic addressing information, while the SSD controller uses the metadata in these commands to perform sequential reordering and management operations, thus keeping the host操作简单while enabling the controller to maintain data integrity.
Solution Approach 2:
The patent implements a mechanism where the SSD controller automatically performs write command reordering and management based on metadata included in the commands received from the host. The controller serves itself by using the embedded metadata to autonomously determine the correct write sequence and manage buffer operations, reducing the need for complex host-side management while maintaining operational simplicity.
Data Source
AI summary
According to one embodiment, a controller of a memory system reorders a plurality of first write commands in an order in which writing within a first zone is executed sequentially from a next write location within the first zone. The controller transfers a plurality of write data associated with the plurality of first write commands reordered from a write buffer of a host to an internal buffer in a same order as the order of the plurality of first write commands reordered, and writes the plurality of write data transferred to the internal buffer to a first storage region managed as the first zone.