Storage System Logical Unit Inquiry Response Handling
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Solution Overview
Problem
Existing storage migration techniques require stopping data exchange between a host computer and storage apparatuses due to incorrect configuration information being returned by the migration destination storage apparatus, leading to recognition of the new storage unit as a new device, necessitating a reboot of the host computer.
Innovation Solution
The storage system manages control information to return appropriate responses to commands for each logical unit, allowing the host system to recognize the migration destination storage apparatus correctly without stopping data exchange by configuring Inquiry information in units of logical units rather than logical devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the migration destination storage apparatus returns configuration information of the migration source storage apparatus, then the host computer can continue data exchange without interruption, but the host computer recognizes the new storage unit as a new device and requires reboot
Solution Approach 1:
The patent applies local quality by differentiating the configuration information returned based on the specific command type and logical unit. Instead of uniformly returning migration source configuration information for all commands, the system selectively returns appropriate configuration information (migration source for Inquiry commands to maintain recognition, migration destination for other commands to ensure proper operation), allowing the host computer to continue operating without reboot while maintaining correct device recognition.
2Adaptability or versatility
If the migration destination storage apparatus returns its own configuration information, then the host computer correctly recognizes the new storage unit, but data exchange must be stopped and host computer rebooted
Solution Approach 1:
The patent implements dynamics by making the configuration information response dynamic and context-dependent. The migration destination storage apparatus dynamically determines what configuration information to return based on the command type (Inquiry vs. other commands) and the logical unit involved. This dynamic response strategy allows the system to maintain both correct device recognition and continuous data exchange without requiring host computer reboot.
3Productivity
If the storage apparatus virtualizes logical units and copies data, then migration can occur without stopping data exchange, but configuration information inconsistency causes recognition issues
Solution Approach 1:
The patent applies segmentation by separating the configuration information management into distinct segments for different command types and logical units. Instead of treating configuration information as a single unified entity, the system segments the response strategy: returning migration source configuration information for Inquiry commands while returning migration destination configuration information for other commands. This segmentation resolves the configuration information inconsistency problem while maintaining high migration productivity.
Data Source
AI summary
A storage system manages control information, which is information related to responses corresponding to prescribed types of commands, for each of a plurality of logical units associated with a logical device, said logical units being provided to one or more host systems. The prescribed types of commands indicating the logical units provided to a first host system, which is one of the one or more host systems, are received from the first host system by the storage system. Responses based on the control information corresponding to the logical units indicated by the received prescribed types of commands are returned to the first host system by the storage system as responses to the received prescribed types of commands.