Storage Controller Snapshot Mapping for Power-Loss Data Recovery
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Solution Overview
Problem
Existing storage devices face data loss due to sudden power cuts or abnormalities, lacking efficient mechanisms for data recovery to a designated normal time point.
Innovation Solution
A storage device with a controller that generates valid and snapshot segments, managing valid pages and snapshot pages to facilitate efficient data recovery by maintaining snapshot data for potential abnormalities, using a buffer memory to store mapping and count tables, and performing background operations to optimize storage efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If snapshot pages are maintained in addition to valid pages, then data recovery capability is improved, but storage space consumption increases
Solution Approach 1:
The patent creates snapshot pages as copies of valid pages at specific points in time. These snapshot pages store historical versions of data, enabling recovery to previous states. The copying mechanism allows the system to maintain multiple versions of data without fundamentally changing the storage architecture, thus improving reliability while managing space through selective retention of snapshots.
Solution Approach 2:
The system performs preliminary actions by creating snapshot pages before potential data loss events occur. These snapshots are prepared in advance as backup copies, allowing the storage device to recover to a designated normal time point when abnormalities occur. This preliminary creation of recovery points addresses the contradiction by having recovery capability ready before it is needed.
2Reliability
If data is recovered to a designated normal time point after abnormality, then data loss is reduced, but recovery time increases
Solution Approach 1:
The system prepares snapshot pages in advance at designated normal time points before abnormalities occur. When data loss prevention is needed, the system can immediately restore from these pre-prepared snapshots rather than creating them during recovery, significantly reducing recovery time while maintaining data loss prevention capability.
Solution Approach 2:
The copying mechanism creates exact replicas of valid data pages at snapshot points. These copies are stored in a ready-to-use state, allowing rapid restoration by simply copying data back to the original location rather than regenerating or reconstructing it during recovery operations, thus minimizing recovery time.
3Productivity
If snapshot segments are generated and managed separately, then data recovery efficiency is improved, but device complexity increases
Solution Approach 1:
The patent divides the storage data into segments: valid segments for current data and snapshot segments for historical data. This segmentation allows independent management and optimization of each type. The controller can efficiently locate and restore from specific snapshot segments without processing entire storage structures, improving recovery efficiency while managing complexity through organized separation of concerns.
Solution Approach 2:
The controller acts as an intermediary that manages the complexity of snapshot segment generation and management. It handles the coordination between valid pages and snapshot pages, automatically creating and managing snapshot segments when needed. This intermediary role abstracts the complexity from the user while enabling efficient recovery operations through structured segment management.
Data Source
AI summary
A storage device is provided to include: a memory including a plurality of storage blocks, each storage block including pages including a valid page to which valid data is written and a snapshot page that stores data corresponding to or associated with data in the valid page; and a controller in communication with the memory and configured to i) generate a valid segment including valid address data indicating an address of the valid page and valid map information indicating a storage location of the valid segment, ii) manage the valid page based on the valid segment and the valid map information, iii) generate a snapshot segment including snapshot address data indicating an address of the snapshot page and snapshot map information indicating a storage location of the snapshot segment, and iv) manage the snapshot page based on the snapshot segment and the snapshot map information.