Storage Path Group Identification Command Optimization
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Solution Overview
Problem
Current computer storage systems face significant overheads in system resources due to the need for multiple Set-Path-Group-ID (SPID) commands to establish logical paths for each storage device during the bring-up process, especially in large systems like IBM zSeries architecture, leading to increased I/O processing and error recovery burdens.
Innovation Solution
A method and system that allow a single Set-Path-Group-ID command to establish logical connections for multiple storage devices, minimizing the overhead by grouping devices and reporting successful or failed additions, thus optimizing the channel command processing and reducing the number of commands required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single SPID command is used to establish logical paths for multiple storage devices, then system overhead is reduced and productivity improves, but device complexity increases due to the need to group and manage multiple devices in a single command
Solution Approach 1:
The patent merges multiple SPID commands into a single command that can simultaneously establish logical paths for multiple storage devices. The command structure allows specifying multiple devices and path groups, enabling the host to bring up multiple devices in one operation rather than requiring separate commands for each device, thereby reducing system overhead and improving productivity.
Solution Approach 2:
The SPID command is enhanced with multi-functionality to handle multiple storage devices and path groups within a single command execution. The command structure enables universal application across different device types and configurations, allowing the host to manage diverse storage architectures efficiently without requiring device-specific command variations.
2Measurement precision
If multiple SPID commands are issued for each storage device during bring-up, then device control precision is maintained, but the number of commands and processing time increases significantly
Solution Approach 1:
Multiple individual SPID commands are merged into a single command structure that can address multiple storage devices simultaneously. The command includes mechanisms to specify multiple device identifiers and path group assignments, allowing the host to establish logical paths for all devices in one operation, thereby reducing bring-up time while maintaining precise control through structured command parameters.
3Reliability
If host channel subsystems manage multiple logical paths for each storage device, then reliability is improved through path redundancy, but I/O processing complexity increases due to concurrent path management
Solution Approach 1:
The patent segments the I/O processing complexity by introducing path group identifiers that organize multiple logical paths into manageable groups. Each path group can be independently managed and assigned to specific devices, allowing the host channel subsystem to handle concurrent path management more efficiently. This segmentation reduces the complexity of tracking and managing individual paths while maintaining the reliability benefits of path redundancy.
Data Source
AI summary
Embodiments of the disclosure relate to setting up a logical path group identification for multiple data storage devices. An aspect of the disclosure concerns a computer implemented method that comprises receiving a host command to establish a group of connection paths between the host and a plurality of storage devices, identifying the group of connection paths, adding each one of the storage devices to the group of connection paths, and reporting to the host those storage devices that could not be successfully added to the group of connection paths. The method maintains host access security to the storage devices by not grouping a device when it is a reset event state.