Storage System Asynchronous Copy Pair Formation Order
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In storage systems with high availability configurations, ensuring data consistency between volumes can be compromised when copy pairs are formed in a particular order, leading to incomplete data reflection and potential failures during system failures.
Innovation Solution
A storage system configuration where the first volume forms a high availability pair, followed by an asynchronous copy pair, and then a standby pair, with specific commands controlling the formation and operation of these pairs to ensure data consistency and integrity, particularly by refusing to form asynchronous copy pairs until the standby pair is established.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the asynchronous copy pair is formed before the standby pair, then the system can start data copying earlier, but data consistency between volumes cannot be ensured during failures
Solution Approach 1:
The standby pair is formed in advance before the asynchronous copy pair. This preliminary action ensures that the journal volume is properly prepared and can correctly receive and reflect update data from the second volume, preventing data consistency issues when the asynchronous copy pair begins operations
Solution Approach 2:
The system establishes the standby pair relationship beforehand to create a protective buffer. This cushioning mechanism ensures that when the asynchronous copy pair starts copying data, the journal volume is already configured to properly handle and reflect update data, preventing potential data consistency failures
2Reliability
If the standby pair is formed first, then data consistency is maintained, but the system complexity increases due to additional formation steps
Solution Approach 1:
The system preemptively forms the standby pair to prevent potential data consistency issues before they can occur. By anticipating and preventing the problem of journal volume data reflection failures, the system avoids the need for complex error handling and recovery mechanisms that would otherwise be required
3Productivity
If both volumes are used as active systems for load balancing, then resource utilization improves, but response time increases due to synchronized writing requirements
Solution Approach 1:
The system segments the copy pair relationships into different types (standby pair and asynchronous copy pair) with different functions. The standby pair handles synchronization requirements while the asynchronous copy pair enables faster data propagation, allowing the system to maintain load balancing while improving response performance for certain operations
Data Source
AI summary
A storage system forms a high availability pair for data duplication using a first volume of a first storage apparatus as a primary volume and a second volume of a second storage apparatus as a secondary volume. The first volume and a third volume of a third storage apparatus are used as a primary volume and a secondary volume, respectively, to form an asynchronous copy pair. The second volume and the third volume are used as a primary volume and a secondary volume, respectively, to form a standby pair. When a command to form the asynchronous copy pair is received, the storage system refuses to form the asynchronous copy pair when the standby pair is not formed yet.