Remote Copy Arbitration Cycle Evaluation Using Test Packets

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Solution Overview

Problem

Existing asynchronous remote copy systems face issues with arbitration failure due to the lower communication stability of UDP communication compared to FC-SCSI, leading to increased data deletion and CPU load, with no clear guidance on setting an appropriate transmission cycle for arbitration instructions.

Innovation Solution

An information processing system that includes management units to transmit test packets at a user-defined cycle, allowing for evaluation of the transmission cycle based on received packet counts, providing users with information for setting an appropriate arbitration instruction cycle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If UDP communication is used for arbitration instructions instead of FC-SCSI, then communication infrastructure cost is reduced, but communication stability deteriorates leading to arbitration failures

Engineering Contradiction:

Improvecommunication infrastructure costVSAvoidarbitration success rate

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The system transmits arbitration instructions with predetermined timing before the actual arbitration point is reached. This advance transmission allows the instruction to be queued and processed in advance, compensating for UDP's lower reliability by ensuring the instruction is already in the system before it's critically needed.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Arbitration instructions are transmitted at regular intervals (periodically) rather than only when absolutely necessary. This periodic transmission ensures that even if some packets are lost, subsequent packets will eventually deliver the arbitration instruction, maintaining system reliability while using cost-effective UDP communication.

Inventive Principle:

Principle #19Periodic action

2Ease of manufacture

If UDP communication is used for arbitration instructions, then communication infrastructure cost is reduced, but data deletion amount increases due to arbitration failures

Engineering Contradiction:

Improvecommunication infrastructure costVSAvoiddata deletion amount

Core Design Contradiction:

Ease of manufactureVSLoss of substance

Solution Approach 1:

By transmitting arbitration instructions in advance with predetermined timing, the system ensures that arbitration can proceed successfully before data deletion becomes necessary. This prevents arbitration failures that would otherwise cause excessive data deletion, thereby reducing data loss while maintaining the cost benefits of UDP communication.

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If UDP communication is used for arbitration processing, then communication infrastructure cost is reduced, but CPU load increases due to additional processing requirements

Engineering Contradiction:

Improvecommunication infrastructure costVSAvoidCPU load

Core Design Contradiction:

Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

Arbitration instructions are transmitted in advance and can be processed during idle CPU periods before the actual arbitration point. This distributes the processing load over time rather than concentrating it at critical moments, reducing peak CPU utilization while maintaining the cost advantages of UDP communication.

Inventive Principle:

Principle #10Preliminary action

4Use of energy by moving object

If arbitration instructions are transmitted with longer intervals, then CPU load is reduced, but arbitration failure risk increases due to UDP communication instability

Engineering Contradiction:

ImproveCPU loadVSAvoidarbitration success rate

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The system uses periodic transmission of arbitration instructions at optimized intervals. This ensures that instructions are sent frequently enough to maintain reliability despite UDP's instability, while the intervals are spaced to avoid excessive CPU load, achieving a balance between both constraints.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

Instructions are transmitted in advance with predetermined timing, allowing the system to use longer intervals between transmissions while still ensuring arbitration success. The advance transmission means the system has more flexibility in timing without compromising reliability.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20260010309A1Information processing system and control method

Publication Date: 2026.01.08 HITACHI VANTARA LTD

AI summary

An information processing system includes a plurality of primary-side storage systems, one or more secondary-side storage systems configured to copy data of the plurality of primary-side storage systems, and one or more hosts configured to control input/output (I/O) of the plurality of primary-side storage systems. Each of the plurality of primary-side storage systems includes a storage controller configured to control I/O, and a management module configured to transmit, to the storage controller, test packets, at a transmission cycle set by a user. The storage controller is configured to receive the test packets transmitted from the management module, and count the number of packets received by the storage controller. The management module is configured to acquire, from the storage controller, the number of received packets, evaluate the transmission cycle based on the number of received packets, and present, to the user, a result of the evaluation.