Passive Cache Entries for Volume Resynchronization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for reseeding volume-level consistency group (CG) relationship information in cross-site storage solutions are inefficient, leading to delays in resynchronization processes, particularly during disruptive operations, which can impact application performance and recovery objectives.
Innovation Solution
The approach involves proactively creating and managing passive cache entries for volume-level CG relationship information, allowing immediate activation during resynchronization, thereby reducing the reseed time period and ensuring timely completion of resynchronization processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If traditional reseed methods are used for volume-level CG relationship information, then system complexity is reduced, but resynchronization delay increases
Solution Approach 1:
The patent applies preliminary action by proactively creating passive cache entries for volume-level CG relationship information before resynchronization is needed. These passive cache entries are prepared in advance and can be quickly activated when a disruptive operation occurs, eliminating the need for time-consuming reseed operations during actual resynchronization events.
Solution Approach 2:
The patent implements dynamics by introducing a state transition mechanism for cache entries between passive and active states. Cache entries dynamically change from passive (pre-created but inactive) to active (fully functional for resynchronization) based on system events, allowing the system to optimize performance without permanent complexity increases.
2Productivity
If passive cache entries are proactively created and managed, then resynchronization speed is improved, but cache management complexity increases
Solution Approach 1:
Passive cache entries are created in advance during normal system operation, storing volume-level CG relationship information before it is needed. This preliminary preparation allows the system to skip the reseed delay during disruptive operations, improving resynchronization speed while managing complexity through automated lifecycle management of these pre-created entries.
Solution Approach 2:
The patent uses copying by creating passive cache entries as copies of the necessary CG relationship information. These copies are maintained in a passive state and can be quickly activated, avoiding the need to recreate or retrieve the information during resynchronization, thus improving speed while keeping management complexity manageable through copy-based approaches.
3Loss of time
If cache entries are activated immediately during resynchronization, then recovery time is reduced, but system performance during disruption increases
Solution Approach 1:
By having passive cache entries ready in advance, the system can immediately activate them when a disruptive operation occurs, minimizing recovery time. The preliminary preparation ensures that the information is available without causing additional I/O disruptions during the actual recovery process.
Solution Approach 2:
The passive cache entries serve as a cushion prepared in advance to absorb the impact of disruptive operations. By having this information pre-prepared in a passive state, the system cushions against the potential performance degradation and I/O disruptions that would otherwise occur during reseed operations, enabling faster recovery with minimal harm to system performance.
Data Source
AI summary
Systems and methods for reducing delays between the time at which a need for a resynchronization of data replication between a volume of a local CG and its peer volume of a remote CG is detected and the time at which the resynchronization is triggered (Reseed Time Period) are provided. According to an example, information indicative of the direction of data replication between the volume and the peer volume is maintained within a cache of a node. Responsive to a disruptive operation (e.g., relocation of the volume from a first node to a second node), the Reseed Time Period is lessened by proactively adding a passive cache entry to a cache within the second node at the time the CG relationship is created when the second node represents an HA partner of the first node and prior to the volume coming online when the second node represents a non-HA partner.