Multi-path Layer Path Selection for Storage Local-Remote Designations
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Solution Overview
Problem
Storage systems with multiple host devices often face performance inefficiencies due to unawareness of storage-side local-remote designations, leading to suboptimal path selection in metro/stretched or active-active configurations where different paths have varying performance characteristics.
Innovation Solution
A multi-path layer in host devices is configured to obtain and adjust path selection based on storage-side local-remote designations, favoring paths to designated 'local' storage systems over 'remote' ones by adjusting weights and algorithms, ensuring optimal performance across heterogeneous storage arrays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the host device uses default path selection without awareness of storage-side local-remote designations, then the system maintains simplicity in path selection logic, but performance is suboptimal due to inability to favor local paths over remote paths
Solution Approach 1:
The host device receives feedback from the storage system about local-remote designations of storage arrays. This feedback mechanism allows the host to adjust its path selection behavior dynamically, favoring local paths when available while maintaining the ability to access remote paths when needed, thus resolving the contradiction between performance optimization and system simplicity
Solution Approach 2:
The path selection logic transitions from static to dynamic by incorporating real-time information about storage array locations. The host device can adaptively change path weights and selection criteria based on current system state and performance requirements, allowing optimal performance without permanent complexity
2Productivity
If the host device implements path selection based on storage-side local-remote designations, then performance is significantly improved by favoring local paths, but the host device becomes aware of and must process storage-side designation information
Solution Approach 1:
The storage system acts as an intermediary that translates complex location-based path selection decisions into simplified guidance for the host device. Rather than requiring the host to independently determine and process detailed storage array locations, the storage system provides curated local-remote designation information that the host can use directly for optimized path selection
3Adaptability or versatility
If multiple storage arrays are configured in metro/stretched or active-active configurations with different performance characteristics, then system versatility and availability are improved, but path selection becomes more complex due to heterogeneous path characteristics
Solution Approach 1:
The path selection mechanism applies different quality criteria to different paths based on their characteristics. Local paths to nearby storage arrays are favored with higher priority, while remote paths to distant arrays are selected when necessary. This local quality approach allows the system to handle heterogeneous storage configurations effectively without requiring complex global optimization logic
Data Source
AI summary
An apparatus in one embodiment includes at least one processing device comprising a processor coupled to a memory. The at least one processing device is configured to obtain in a host device information characterizing local-remote designations of respective first and second storage systems, one of which is designated as local and one of which is designated as remote, and to adjust path selection in a multi-path layer of the host device based at least in part on the obtained information characterizing the local-remote designations of the respective first and second storage systems. In some embodiments, a given logical storage device is accessible to the multi-path layer of the host device via a first set of paths to the first storage system and a second set of paths to the second storage system, and adjusting path selection in the multi-path layer comprises adjusting weights assigned to respective ones of the paths.