HBA Virtualization-Aware MPIO Failover Path Selection
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Solution Overview
Problem
Conventional host device multi-pathing arrangements are not aware of and not aligned with HBA virtualization arrangements, leading to the selection of non-optimal paths in case of IO operation failures, resulting in less-effective multi-pathing policies.
Innovation Solution
The implementation of HBA virtualization aware multi-pathing decisions by identifying details of virtual HBAs and their respective backing physical HBAs, allowing for path hierarchical considerations in selecting alternative paths for retrying failed IO operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional multi-pathing failure policies are used, then path selection is simple, but path selection is not aligned with HBA virtualization arrangements leading to non-optimal paths
Solution Approach 1:
The MPIO driver incorporates feedback mechanisms to detect HBA virtualization arrangements and adjust path selection accordingly. By monitoring the virtualization layer and receiving information about virtual HBAs and their backing physical HBAs, the system dynamically modifies failover policies to align with the virtualization architecture, resolving the contradiction between simple path selection and effective multi-pathing.
Solution Approach 2:
The system changes the parameters of path selection by introducing awareness of HBA virtualization layers. The MPIO driver now considers virtual HBA identifiers and physical HBA mappings when selecting paths, transforming the path selection process from a simple conventional approach to a virtualization-aware approach that optimizes reliability.
2Measurement precision
If HBA virtualization aware path selection is implemented, then path selection accuracy is improved, but detection and identification complexity increases
Solution Approach 1:
The MPIO driver acts as an intermediary layer between the host device and storage system, specifically designed to detect and manage HBA virtualization arrangements. This intermediary component handles the complexity of identifying virtual HBAs and their physical counterparts, providing accurate path identification without burdening the entire system with detection complexity.
Solution Approach 2:
The system performs preliminary detection and identification of HBA virtualization arrangements during path setup and configuration. By pre-identifying virtual HBA instances and their backing physical HBAs before IO operations occur, the system stores this information for use during failover decisions, reducing real-time detection complexity while maintaining high path identification accuracy.
Data Source
AI summary
A host device is configured to communicate over a network with a storage system comprising a plurality of storage devices. The host device comprises a multi-path input-output (MPIO) driver configured to control delivery of input-output (IO) operations from the host device to the storage system over a plurality of paths through the network. The MPIO driver is further configured to identify whether given ones of a plurality of initiators associated with the paths comprise given ones of a plurality of virtual initiator instances, and to identify given ones of a plurality of physical initiator components corresponding to the given ones of the virtual initiator instances. The MPIO driver is also configured to detect a failure of an IO operation over a first path, and to select a second path for retrying the IO operation based on the identification of the physical initiator components corresponding to the virtual initiator instances.