Storage System Scatter Write Atomic Data Consistency

Solution Overview

Problem

Storage systems fail to maintain data consistency when handling scatter write atomic (SWA) commands, as they may not ensure that all data is written correctly before transmitting a response, leading to potential inconsistencies in the state of data before and after the write process.

Innovation Solution

A storage system with a processor and memory that manages logical volumes and device storage areas, ensuring that write data is received and stored in different storage areas, and only transmitting a success response once all data is written, with a failure response if any data is not written, thereby maintaining data consistency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the storage apparatus writes all data designated by the parameter list to designed storage areas and transmits a normal end response, then the write process completes, but data consistency cannot be ensured if a write process ends due to an obstacle before the response is transmitted

Engineering Contradiction:

Improvedata consistencyVSAvoidwrite process control

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The storage apparatus transmits the SWA command and parameter list to the host computer before actually writing the data to storage areas. This preliminary action allows the host to prepare and verify data, ensuring that if a write fails, the host can detect the inconsistency and handle it appropriately, thereby maintaining data consistency without requiring complex write process control in the storage apparatus

Inventive Principle:

Principle #10Preliminary action

2Loss of time

If the storage apparatus transmits a normal end response immediately after receiving the SWA command, then the response time is short, but data consistency is not maintained if write processes fail

Engineering Contradiction:

Improveresponse timeVSAvoiddata consistency

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The storage apparatus transmits the SWA command and parameter list to the host computer before actually writing the data to storage areas. This preliminary action allows the host to prepare and verify data, ensuring that if a write fails, the host can detect the inconsistency and handle it appropriately, thereby maintaining data consistency without requiring complex write process control in the storage apparatus

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9952805B2Storage system and data write method using a logical volume to either store data successfully onto a first memory or send a failure response to a server computer if the storage attempt fails

Publication Date: 2018.04.24 HITACHI VANTARA LTD

AI summary

A processor receives a command from a server computer to designate a plurality of addresses related to a plurality of logical storage areas, and write a plurality of write data to the logical storage areas. The processor receives the write data and writes it to storage areas different from storage areas in which a plurality of holding data are stored in a first memory. When the processor determines that the write data are written to the first memory, the processor transmits a success response to a host computer. When the write data satisfy a predetermined condition, the processor writes the write data in the first memory to a plurality of first device storage areas. When it is determined that at least a part of the data is not written to the first memory, the processor transmits a failure response to the host computer.