SSD Superblock Segmentation for Targeted Garbage Collection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current SSD garbage collection methods in FDP mode overburden the SSD by not differentiating between superblocks containing data streams that obey FDP rules and those that do not, leading to unnecessary garbage collection and increased write amplification.
Innovation Solution
A method where the controller associates superblocks with data streams and identifies 'bad' superblocks that do not satisfy FDP criteria, performing garbage collection only on these bad superblocks while allowing other superblocks to be deallocated without garbage collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If garbage collection is performed on all superblocks in FDP mode, then data management is simplified, but write amplification increases and performance degrades
Solution Approach 1:
The patent segments superblocks into two distinct categories: FDP-mode superblocks and non-FDP-mode superblocks. This segmentation allows differential garbage collection strategies to be applied to each type, avoiding unnecessary garbage collection on FDP-mode superblocks that don't require it, thereby reducing write amplification while maintaining simplified data management where applicable.
Solution Approach 2:
The patent applies local quality by implementing different garbage collection behaviors for different types of superblocks. FDP-mode superblocks receive no garbage collection (or minimal intervention), while non-FDP-mode superblocks undergo traditional garbage collection. This localized approach optimizes performance for each superblock type based on its specific requirements.
2Reliability
If garbage collection is performed on all superblocks, then stale data is cleared uniformly, but SSD performance and lifespan are reduced due to excessive write operations
Solution Approach 1:
The patent segments the superblock population into FDP-mode and non-FDP-mode categories, applying targeted garbage collection only where needed. This segmentation ensures reliable stale data clearance for non-FDP superblocks while preserving SSD performance by avoiding unnecessary write operations on FDP superblocks that manage their own data lifecycle.
Solution Approach 2:
The patent applies partial action by performing garbage collection on only a subset of superblocks (non-FDP-mode) rather than all superblocks. This partial approach provides sufficient stale data clearance for the subset that needs it, while avoiding the excessive write operations that would degrade overall SSD performance.
3Device complexity
If superblocks are mixed into the same pool regardless of data stream compliance, then resource management is simplified, but unnecessary garbage collection is triggered
Solution Approach 1:
The patent segments the superblock pool into distinct FDP-mode and non-FDP-mode groups, maintaining separate management tracks for each. This segmentation prevents unnecessary garbage collection triggers by keeping compliant FDP superblocks separate from non-compliant ones, reducing overall garbage collection frequency while maintaining manageable resource organization.
Solution Approach 2:
The patent applies local quality by implementing different management characteristics for different superblock types. FDP-mode superblocks are managed with minimal intervention and no garbage collection, while non-FDP-mode superblocks receive active management including garbage collection. This localized management approach optimizes productivity by reducing unnecessary operations.
Data Source
AI summary
A method for writing data to a solid-state drive (SSD) configured to store data in a plurality of memory dies each comprising a plurality of memory blocks. The plurality of memory blocks are logically organized as a plurality of superblocks. The method is performed by a controller in communication with the plurality of memory dies. The method comprises associating a superblock of the plurality of superblocks with a data stream of a plurality of data streams received via a write command from a host interface. The method also comprises writing each data stream to the memory blocks of the respective superblock. The method also includes identifying a superblock as a bad superblock if the data stream written to the memory blocks of the superblock does not satisfy a predetermined criteria. Further, the method includes executing garbage collection only on the memory blocks of the bad superblocks.