Storage Controller Mapping Update via Copy Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In storage systems with multiple controllers sharing storage areas, the frequent reference to mapping information during garbage collection (GC) leads to increased overheads and performance deterioration due to inter-controller notifications, especially when data relocation occurs, as the current technologies do not effectively manage mapping information updates efficiently.
Innovation Solution
A storage system where each controller manages its assigned storage areas independently, with one controller handling garbage collection and updating its mapping information, and another controller acquiring and updating the mapping information post-migration, thereby reducing the need for inter-controller notifications and references to mapping information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If mapping information is shared among controllers to enable inter-LU deduplication, then data reduction capability is improved, but inter-controller notification overhead increases during GC operations
Solution Approach 1:
The patent implements a copy mechanism where the second controller creates a copy of the updated mapping information from the first controller. This allows the second controller to have local access to mapping data without requiring continuous real-time synchronization, thereby reducing inter-controller notification overhead while maintaining the capability to perform deduplication operations across LUs managed by different controllers.
2Measurement precision
If mapping information is updated frequently during write operations, then data access accuracy is improved, but inter-controller communication frequency increases
Solution Approach 1:
The patent segments the storage system into multiple controllers, each independently managing mapping information for specific LUs. This segmentation allows write operations to be processed locally without requiring inter-controller communication for every mapping update, thereby improving write operation efficiency while maintaining data access accuracy through localized mapping management.
Solution Approach 2:
The patent introduces an intermediary mechanism where mapping information is copied from the first controller to the second controller rather than requiring direct real-time communication for every update. This intermediary copy mechanism reduces the frequency of inter-controller communication during write operations while ensuring that mapping information remains accurate for data access operations.
3Productivity
If each controller manages its own storage areas independently, then controller process performance is improved, but mapping information consistency across controllers becomes difficult to maintain
Solution Approach 1:
The patent uses a copying mechanism where the second controller obtains a copy of mapping information from the first controller. This allows each controller to independently manage its storage areas and maintain high process performance, while the copy mechanism ensures that mapping information consistency is maintained across controllers without requiring continuous synchronization communication.
Data Source
AI summary
A first controller manages first mapping information for accessing data stored in a storage area, management of which is assigned to the first controller, and second mapping information for accessing data stored in a predetermined storage area, management of which is assigned to a second controller. The second controller, when having executed garbage collection on the predetermined storage area, changes mapping information to post-migration mapping information for accessing data after being migrated by the garbage collection. The first controller acquires the post-migration mapping information from the second controller, and updates the second mapping information using the post-migration mapping information when information in the second mapping information and is to be used for accessing the data in the predetermined storage area has been updated accompanying the garbage collection when the first controller accesses the data in the predetermined storage area after the garbage collection by using the second mapping information.