Common Logical Volume for Storage Replication Failover
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Solution Overview
Problem
Current storage replication systems face challenges in managing multi-site disaster recovery environments, leading to manual and costly procedures for data management, failover processing, and increased Recovery Time Objective (RTO) and Recovery Point Objective (RPO), due to the need for manual correlation of primary and secondary volumes with different SCSI device identifiers and limited integration with storage vendors.
Innovation Solution
The system introduces a common logical volume with a shared device identifier across all storage systems in a replication group, allowing for automated data replication and failover processing transparent to host systems, using replication links to exchange information and detect failures, thereby simplifying management and reducing manual intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual correlation of primary and secondary volumes with different SCSI device identifiers is used, then data integrity can be maintained, but management complexity and time consumption increase significantly
Solution Approach 1:
The patent introduces a common logical volume with a shared device identifier that acts as an intermediary between primary and secondary physical volumes. This logical volume with identifier 5005 is accessible from both primary storage system 5002 and secondary storage system 5004, eliminating the need for manual correlation of different SCSI device identifiers while maintaining data integrity through the replication link 5006.
Solution Approach 2:
The common logical volume serves multiple functions simultaneously: it provides a unified access point for host systems, maintains replication relationships across multiple sites, and enables automated failover. This universal interface simplifies management while preserving the reliability benefits of having distinct primary and secondary volume identifiers.
2Reliability
If manual failover processing procedures are used, then system reliability can be ensured, but Recovery Time Objective (RTO) increases
Solution Approach 1:
The system enables automated failover where the storage systems themselves perform the failover processing without requiring manual intervention. When primary storage system 5002 fails, secondary storage system 5004 can automatically assume the role by accessing the common logical volume 5005, significantly reducing RTO while maintaining system reliability through the pre-configured replication relationship.
Solution Approach 2:
The replication link 5006 continuously maintains synchronized copies of data between primary and secondary storage systems before any failure occurs. This preliminary replication ensures that when failover is needed, the secondary system already has up-to-date data ready for immediate service continuation, reducing both RTO and Recovery Point Objective (RPO).
3Reliability
If different SCSI device identifiers are used for primary and secondary volumes, then data integrity is maintained, but integration with storage vendors and automation capability are limited
Solution Approach 1:
The patent segments the storage system into three distinct layers: primary physical volumes with unique identifiers, secondary physical volumes with unique identifiers, and a common logical volume with a shared identifier. This segmentation allows each layer to maintain its specific function while the logical volume layer provides the unified interface needed for automation and vendor integration.
Solution Approach 2:
The common logical volume acts as an intermediary layer that reconciles the need for different physical volume identifiers with the requirement for automated integration. It provides a universal access point that storage vendor management software can interact with automatically, while the underlying physical volumes maintain their distinct identifiers for data integrity purposes.
Data Source
AI summary
Systems and methods for management of replicated storage. Features and aspects hereof provide management of data replication among a plurality of storage systems in a manner substantially transparent to host systems attached to the storage systems. The storage systems are coupled to one another through a replication link. One storage systems is designated the primary storage system and all others are designated secondary storage systems. A common logical volume is defined with a common logical volume device identifier used by all of the replicating storage systems of a replication group and their respective attached host systems. The primary storage system processes I/O requests directed to the logical volume by accessing its physical storage volume and forwarding the request to be replicated to all secondary storage systems over the replication link. Secondary storage systems process I/O requests by shipping them over the replication link to the primary storage system for processing.