Asynchronous Consistency Group Pause for Storage Replication
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Solution Overview
Problem
Current data replication technologies do not allow for efficient pausing of consistency group formation, limiting the ability to create additional copies of data at a secondary storage site without overwriting newer data.
Innovation Solution
A method and system for asynchronously pausing the formation of consistency groups, allowing a host to suspend the first copy operation after initiating a second copy operation, enabling further processing of the first data copy and subsequent creation of additional copies before resuming consistency group formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If replication from primary to secondary site is suspended to allow reverse FlashCopy operations, then additional copies can be created from the second copy, but the first copy operation must be suspended which delays consistency group formation and reduces replication efficiency
Solution Approach 1:
The patent segments the copy operation into distinct phases: first copy operation (source to first copy), second copy operation (first copy to second copy), and resumption phase. By suspending only the first copy operation temporarily while completing the second copy operation, the system allows reverse FlashCopy to create additional copies without permanently halting replication, thus maintaining overall productivity while enabling versatility.
2Productivity
If the first copy operation continues without suspension, then replication efficiency is maintained, but newer data may be overwritten when creating additional copies from the second copy
Solution Approach 1:
The patent applies preliminary action by suspending the first copy operation before initiating the reverse FlashCopy operation. This ensures that the first copy remains at a consistent point-in-time state, preventing newer data from being overwritten when creating additional copies. The suspension is temporary and controlled, allowing the system to maintain data consistency while eventually resuming replication to restore productivity.
3Measurement precision
If consistency group formation is paused asynchronously, then point-in-time consistency is maintained for creating additional copies, but the formation of next consistency group is delayed until resume command
Solution Approach 1:
The patent implements periodic action through the suspend-resume mechanism. The first copy operation is periodically suspended to allow reverse FlashCopy operations, then resumed to continue consistency group formation. This periodic interruption maintains precise point-in-time consistency when needed while minimizing overall time loss by quickly resuming replication after the temporary suspension.
Data Source
AI summary
Provided are a computer program product, system, and method for asynchronous pausing of the formation of consistency groups. A first copy operation is initiated to copy the source data from the first storage to the first data copy in the second storage. A second copy operation is initiated to copy the first data copy in the second storage to a second data copy in response to forming a consistency group of the source data at the first data copy forms consistent as of a point-in-time with respect to the source data. The first copy operation is suspended to allow for further processing of the first data copy in response to completing the second copy operation. The formation of a next consistency group is restarted between the source data and the first data copy in response to receiving a resume command.