Remote Copy Pair Status Switching for Backup Reliability

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Solution Overview

Problem

The existing backup method linking in-storage copy and synchronous remote copy functions is vulnerable to failures in the remote copy source site, which can prevent data backup at both remote copy destination sites.

Innovation Solution

The computing system sets the pair status of remote copy destination volumes to a mode for terminating remote copy before initiating in-storage copy and then changes it to a mode for starting remote copy, ensuring that at least one remote copy destination site can maintain data backup even if a failure occurs in the copy source volume.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If synchronous remote copy is used to ensure high backup reliability, then backup reliability is improved, but copy time increases significantly when distance between storage systems is large

Engineering Contradiction:

Improvebackup reliabilityVSAvoidcopy time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent segments the backup process into two independent parallel paths: synchronous remote copy to a first storage system and asynchronous remote copy to a second storage system. This segmentation allows each path to operate independently with different performance characteristics, resolving the contradiction between reliability and time by providing both immediate backup (synchronous) and eventual backup (asynchronous) without blocking each other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic switching between synchronous and asynchronous remote copy modes based on system state and distance conditions. The system can dynamically select which copy mode to use for different data volumes or under different failure conditions, optimizing the balance between backup reliability and copy time according to actual operational requirements.

Inventive Principle:

Principle #15Dynamics

2Productivity

If asynchronous remote copy is used to improve copy efficiency over large distances, then copy efficiency is improved, but backup reliability decreases

Engineering Contradiction:

Improvecopy efficiencyVSAvoidbackup reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent divides the backup destination into two separate storage systems: one for synchronous copy and one for asynchronous copy. This segmentation ensures that the asynchronous path does not compromise the reliability of the synchronous path, as each path maintains its own independent backup mechanism with different reliability guarantees.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the operational parameters of the remote copy system by implementing mode switching between synchronous and asynchronous copy based on distance, performance requirements, and failure conditions. This allows the system to optimize copy efficiency when distance is large while maintaining reliability when needed.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If multi-target type remote copy is implemented with both synchronous and asynchronous destination sites, then fault tolerance is improved, but system complexity increases

Engineering Contradiction:

Improvefault toleranceVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the remote copy architecture into distinct synchronous and asynchronous copy paths to different storage systems. This segmentation simplifies the management of multiple copy targets by providing clear separation of functions, making it easier to implement, monitor, and maintain while achieving improved fault tolerance.

Inventive Principle:

Principle #1Segmentation

4Reliability

If in-storage copy function is combined with synchronous remote copy function, then backup reliability is improved, but vulnerability to copy source failure increases

Engineering Contradiction:

Improvebackup reliabilityVSAvoidvulnerability to copy source failure

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the backup architecture into independent in-storage copy, synchronous remote copy, and asynchronous remote copy paths. This segmentation ensures that a failure in the copy source volume does not propagate to all backup destinations, as each path has its own independent copy mechanism and can fail independently.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements beforehand cushioning by establishing asynchronous remote copy to a second storage system as a backup backup mechanism. This secondary backup path acts as a cushion against failures in the primary synchronous copy path or copy source, ensuring that data can be recovered even if the primary backup mechanism fails.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS8745006B2Computing system and backup method using the same

Publication Date: 2014.06.03 HITACHI VANTARA LTD

AI summary

This invention provides a computing system in which multiple remote copy destination sites exist and, even if a failure occurs in a copy source volume in a remote copy source site, it becomes possible in at least one remote copy destination site to establish backup in which data must be determined at a certain point in time. The computing system of this invention is characterized by, before the in-storage copy function performing in storage copy in the remote copy source site, setting the pair status of the remote copy destination volume in at least one storage system in multiple remote copy destination storage systems and the remote copy source volume to the mode for terminating remote copy and, after the in-storage copy is completed, changing the above-mentioned pair status to the mode for starting remote copy.