Remote Point-in-Time Copy for Mirror Storage Relationships
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Solution Overview
Problem
Existing point-in-time copy technologies face challenges in maintaining continuous availability of mirror storage relationships during remote FlashCopy operations, particularly when primary storage becomes the target of a FlashCopy operation, leading to potential interruptions and performance impacts.
Innovation Solution
The system establishes indicators for source and target copy relationships to determine whether to use a remote first type of copy operation, allowing for ambiguity resolution and efficient data transfer between secondary storages in mirror relationships, ensuring seamless remote point-in-time copy operations without interrupting mirror copy relationships.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a remote FlashCopy operation is performed from a source volume to a target volume when both are primary volumes in mirror copy relationships, then the point-in-time copy operation can be completed, but the mirror copy relationships may be interrupted and continuous availability is compromised
Solution Approach 1:
The copy operation is segmented into two distinct phases: first performing the FlashCopy operation locally between source and target primary volumes, then separately performing a second FlashCopy operation from the secondary volumes at the remote site. This segmentation allows the mirror copy relationships to be maintained while completing the remote PiT copy operation.
Solution Approach 2:
The system performs preliminary actions by establishing the local FlashCopy relationship between source and target primary volumes before initiating the remote FlashCopy operation. This preliminary setup ensures that the mirror copy relationships remain intact and continuous availability is maintained throughout the operation.
2Measurement precision
If data is FlashCopied from source and target primary volumes to secondary volumes at a remote site, then the remote PiT copy is achieved, but system performance is impacted due to additional data transfer operations
Solution Approach 1:
The invention merges the remote PiT copy operation with the existing mirror copy infrastructure by performing FlashCopy operations at both the primary volume level and secondary volume level simultaneously. This combining approach achieves precise point-in-time copying while utilizing the existing mirror copy mechanisms to minimize performance impact.
3Reliability
If the mirror copy relationship is maintained during FlashCopy operations, then continuous availability is preserved, but the complexity of managing multiple copy relationships increases
Solution Approach 1:
The system implements self-service by automatically managing the multiple FlashCopy relationships through the Remote Pair FlashCopy operation. The storage system autonomously handles the coordination between local and remote FlashCopy operations, maintaining mirror relationships without requiring manual intervention, thus preserving continuous availability while simplifying operation.
Data Source
AI summary
Provided are a computer program product, system, and method for performing a remote point-in-time copy to a source and target storages in further mirror copy relationships. Each of a plurality of source copy relationships is from the source storage to one corresponding source copy storage. Each of a plurality of target copy relationships is from the target storage to one corresponding target copy storage, where in each relationship an indicator indicates whether to use a remote first type copy operation. The first type copy operation is used to copy data from the source storage to the target storage and copy data from the source copy storage to the target copy storage for the determined source and target copy relationships having the indicator set. A second type of copy operations is used for source and target relationships not having the indicator set.