Storage Controller Volume Copying Rollback Mechanism
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Solution Overview
Problem
Existing storage systems face a decline in response performance during the volume copying process, particularly when copying a core-operation volume, as the data saving process for writing requests deteriorates the performance.
Innovation Solution
A storage system with a controller that manages address conversion information and history, allowing for the insertion of a start marker during the copying process, generating a copy-destination volume, and resetting the address conversion information to maintain data consistency and performance by avoiding the data saving process at the write trigger.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If data of the core-operation volume is saved using a core-operation volume write process request, then the volume copying process can be performed while continuing access, but the response performance to the writing process deteriorates
Solution Approach 1:
The patent segments the address conversion information management by introducing a separate addition volume to store update data, while the core-operation volume maintains its original write process. This segmentation allows the copying process to proceed without blocking normal write operations, resolving the contradiction between copying capability and response performance.
Solution Approach 2:
The patent performs preliminary actions by pre-storing update data in the addition volume before the actual copy operation. When a copy is requested, the system uses the pre-stored update data and address conversion information to create the copy, eliminating the need to save data during the copy process and thus maintaining response performance.
2Reliability
If address conversion information is updated during copying, then data consistency can be maintained, but the copying process becomes more complex
Solution Approach 1:
The patent introduces an intermediary structure (the addition volume with update data) that mediates between the core-operation volume and the copy process. This intermediary stores address conversion information and update data, allowing the copying process to access consistent information without directly manipulating the core volume's address conversion tables, thus maintaining data consistency while simplifying the copy logic.
Solution Approach 2:
The patent uses copying of address conversion information from the core-operation volume to the copy-destination volume as a key mechanism. By copying the address conversion tables and applying pre-stored update data, the system maintains data consistency without requiring complex real-time updates during the copy process.
Data Source
AI summary
In a storage system having a controller constructing a provision volume provided to a server system and an addition volume in which data to be stored in the provision volume is added and stored, when a provision volume copying instruction is received, the controller inserts a start marker indicating start time point of copying into address change history information and copies address conversion information of a provision volume while receiving update data to a provision volume from the server system, as address conversion information of a copy-destination volume. On the basis of a start marker of address change history information and history information, a change from start to completion of copying of the address conversion information of a copy-destination volume is reset to a state at the start time point of copying.