Flash Storage Garbage Collection Metadata Tag Consolidation
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Solution Overview
Problem
Flash storage devices experience increased latency due to scattered host data files resulting from flash memory management techniques, which require multiple read operations to retrieve requested data files, thereby degrading performance.
Innovation Solution
The optimization of garbage collection in flash storage devices is achieved by grouping host data units with a specific metadata tag, allowing for the identification and buffering of these units during maintenance operations, and writing them back to physically proximate locations, thereby reducing the number of read operations needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If flash memory management techniques are used to maximize the life of flash memory, then the number of program/erase cycles is reduced, but host data files become scattered across flash memory requiring multiple read operations
Solution Approach 1:
The patent performs preliminary actions during garbage collection by identifying host data units with matching metadata tags and pre-positioning them in transfer buffers before write operations. This advance preparation ensures that when read operations occur, the data is already consolidated and ready, eliminating the need for multiple read operations and reducing read latency while preserving flash memory life through optimized P/E cycle management
Solution Approach 2:
The patent merges host data units that share the same metadata tag into the same flash data unit during garbage collection. By combining scattered data units with identical tags into single consolidated units, the system reduces the number of separate read operations needed to retrieve complete host data files, thereby reducing read latency without compromising flash memory durability
2Reliability
If host data files are scattered across flash memory to maximize memory life, then program/erase cycle distribution is improved, but the number of read operations required increases
Solution Approach 1:
During garbage collection, the controller performs preliminary identification and buffering of host data units with matching metadata tags. This advance consolidation prepares data for efficient retrieval without requiring multiple read operations, thus maintaining data retrieval efficiency while preserving flash memory durability through optimized write amplification reduction
Solution Approach 2:
The patent introduces transfer buffers as intermediary storage between flash memory and the host system. These buffers temporarily hold consolidated host data units with matching metadata tags, allowing the system to retrieve complete data files in fewer operations. The intermediary buffer decouples the scattered physical storage from the logical data retrieval process, maintaining both memory durability and retrieval efficiency
3Loss of information
If multiple read operations are performed to retrieve scattered host data files, then complete data retrieval is achieved, but latency in responding to read commands increases
Solution Approach 1:
The system performs preliminary consolidation of host data units with matching metadata tags into the same flash data units during garbage collection operations. This advance grouping ensures that when a read command is received, the complete host data file can be retrieved in fewer read operations, significantly reducing response time while maintaining data completeness
Solution Approach 2:
By merging host data units with identical metadata tags into consolidated flash data units, the patent enables complete host data files to be stored in fewer physical locations. This consolidation reduces the number of read operations from multiple scattered locations to fewer consolidated locations, maintaining full data completeness while reducing read command response latency
Data Source
AI summary
A method for managing data in a flash storage system includes reading multiple flash data units in the flash storage system. At least some host data units are stored in each flash data unit is associated with a workload by a metadata tag, and the host data units have dissimilar metadata tags. The method also includes identifying host data units having the same first metadata tag from the host data units read from the read flash data units. The same first metadata tag is stored with each identified host data unit at a time of writing each identified host data unit to a respective flash data unit, from which the identified host data unit was read. The identified host data units with same first metadata tag are written to a first available flash data unit in the flash storage system.