MPIO Driver Automatic Standby for Active-Active Storage
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Solution Overview
Problem
Storage arrays in active-active configurations experience performance degradations due to network switch fabric reconfigurations, leading to issues like RSCN storms that impact IO operations and data replication reliability.
Innovation Solution
A multi-path layer with automatic standby setting functionality is implemented in host devices, using MPIO drivers to separate paths into active and standby sets based on performance, avoiding IO operations over degraded paths and dynamically switching modes to maintain optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If paths are used to communicate with multiple storage arrays in active-active configuration, then data replication and failure recovery are improved, but performance degradations occur due to fabric reconfigurations and RSCN storms
Solution Approach 1:
The patent segments the paths into distinct sets (first set of paths to first storage system, second set of paths to second storage system) and assigns them different operational modes (active vs standby). This segmentation allows the system to isolate performance issues in one path set while maintaining operational capability through the other set, thereby resolving the contradiction between using multiple paths for reliability and avoiding performance degradations.
Solution Approach 2:
The patent implements dynamic mode switching where the MPIO driver can automatically interchange standby and active modes based on real-time performance monitoring. When performance degradation is detected in the active path set, the system dynamically switches to the standby path set, ensuring continuous optimal performance while maintaining the ability to replicate data across multiple storage arrays for failure recovery.
2Productivity
If automatic standby setting is implemented to avoid fabric-related performance degradations, then IO operation performance is improved, but path selection complexity increases
Solution Approach 1:
The patent implements self-service path selection where the MPIO driver automatically monitors path performance and makes decisions about active/standby mode assignment without requiring manual intervention. The driver uses built-in performance monitoring to detect fabric-related issues and autonomously switches path modes, improving IO performance while containing complexity within the driver itself rather than requiring external management.
Solution Approach 2:
The patent employs feedback mechanisms where the MPIO driver continuously monitors path performance and uses this information to adjust path mode assignments. This closed-loop feedback allows the system to adapt to changing fabric conditions in real-time, maintaining optimal performance while managing complexity through automated decision-making based on measured performance metrics.
3Object-affected harmful factors
If paths are separated into active and standby sets, then exposure to fabric-related issues is reduced, but configuration complexity increases
Solution Approach 1:
The patent segments paths into distinct active and standby sets, which simplifies the approach to protecting against fabric issues by creating clear separation between operational and backup paths. This segmentation makes it easier to manage and understand path roles compared to more complex load-balancing or failover mechanisms, thereby reducing configuration complexity while effectively reducing exposure to harmful fabric-related degradations.
Solution Approach 2:
The patent implements preliminary action by pre-configuring standby paths ready to activate when fabric-related performance degradations occur. The standby paths are prepared in advance but remain inactive until needed, allowing the system to quickly respond to fabric issues without requiring complex real-time configuration changes. This pre-prepared approach simplifies configuration while providing effective protection against fabric-related problems.
Data Source
AI summary
A first host device in an illustrative embodiment comprises a multi-path input-output (MPIO) driver configured to separate paths from the first host device to first and second storage systems into a first set of paths to the first storage system and a second set of paths to the second storage system, and to monitor performance of at least subsets of the first and second sets of paths. Responsive to detection of a performance deviation between the first and second sets of paths that exceeds a specified threshold, the MPIO driver automatically places the paths of the set exhibiting lower performance in a standby mode of operation and the paths of the other set in an active mode of operation. Absent any such performance deviation, the MPIO driver automatically places the paths of one of the sets in the standby mode of operation and the paths of the other one of the sets in the active mode of operation.