Solid-State Memory Mapping Table Metadata Recovery
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Solution Overview
Problem
Solid-state memory (SSD) systems lack a method for recovering metadata consistency after a power-off event, leading to potential operational failures and prolonged boot times due to the need to load large mapping tables upon power-on.
Innovation Solution
A method and electronic device that utilize a secondary mapping table stored in SSD flash, with a primary mapping table containing physical addresses and identifying information, allowing for automatic metadata recovery and reduced loading times by using a two-level mapping mechanism and flags for access history.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the whole metadata information is loaded when the solid-state memory is powered on, then the mapping table can be complete and accurate, but the response time for power-on becomes long
Solution Approach 1:
The patent divides the metadata into multiple chunks and stores them in the flash memory. Only the first chunk is loaded into RAM during power-on, while other chunks are loaded on-demand based on access patterns. This segmentation reduces the initial loading time while maintaining the ability to access complete metadata when needed.
Solution Approach 2:
The patent pre-loads only the essential first chunk of metadata into RAM during power-on, rather than waiting to load all metadata. This preliminary action allows the system to become operational faster, with the understanding that additional metadata chunks will be loaded as needed during normal operation.
2Speed
If the mapping table is stored entirely in RAM for fast access, then the read/write speed improves, but the cost and power consumption increase
Solution Approach 1:
The patent segments the mapping table into multiple chunks stored in flash memory, with only the first chunk resident in RAM. This allows the system to maintain fast access speeds for commonly accessed data while reducing the RAM capacity requirement to hold only a portion of the total mapping table.
Solution Approach 2:
The patent introduces a hybrid storage architecture where flash memory serves as an intermediary between the complete mapping table and the limited RAM capacity. The first chunk acts as a buffer in RAM, while other chunks remain in flash, mediating between the need for speed and the constraint on memory quantity.
3Device complexity
If no recovery mechanism is implemented for metadata, then the system structure remains simple, but data security and operational reliability deteriorate after power-off abnormalities
Solution Approach 1:
The patent implements a recovery mechanism where the first chunk of metadata is pre-loaded into RAM during power-on. This preliminary action ensures that critical mapping information is available in volatile memory before any operations occur, enabling recovery if power is lost during subsequent operations. The system can reconstruct the complete mapping table from this preserved first chunk.
Solution Approach 2:
The patent creates a protective cushion by storing the first chunk of metadata in both flash and RAM simultaneously. This redundant storage acts as a safety buffer against power-loss corruption, ensuring that even if power is lost during normal operation, the critical mapping information remains intact and can be used to recover the system state.
Data Source
AI summary
The invention provides a method and electronic device for a mapping table in a solid-state memory, wherein the mapping table comprises a primary mapping table and a secondary mapping table. The method comprises: mapping all logic pages from a host to physical pages of a flash on the solid-state memory in the unit of page to form the secondary mapping table, the secondary mapping table being stored in the flash on the solid-state memory; acquiring a first physical address which is the physical address of a first chunk of the secondary mapping table in the flash of the solid-state memory; and forming and storing the primary mapping table in the flash of the solid-state memory, wherein the first physical address and corresponding first identifying information form a mapping relationship in a mapping element of the primary mapping table, the first identifying information being identifying information of the first chunk.