Redundant Storage Virtualization Subsystem Branching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The Serial Attached SCSI (SAS) protocol is not suitable for implementing a redundant storage virtualization subsystem (SVS) due to its limitations, particularly in loop connectivity, necessitating a workable device-side connectivity solution for SAS in SVS.
Innovation Solution
A redundant storage virtualization subsystem is configured with a pair of storage virtualization controllers (SVCs) and physical storage devices, featuring multiple redundant data paths that can switch access when one path becomes inaccessible, utilizing signal integrity enhancing devices (SIEDs) and branching boards to ensure continuous data access through accessible paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SAS protocol is used for storage virtualization subsystem, then point-to-point serial signal transmission is achieved, but loop connectivity capability is lost
Solution Approach 1:
A branching board is introduced as an intermediary device to enable loop connectivity in SAS-based storage virtualization subsystems. The branching board receives serial signals from storage virtualization controllers and distributes them to multiple physical storage devices, thereby creating virtual loop connectivity while maintaining SAS point-to-point transmission characteristics. This intermediary component resolves the contradiction by adding loop capability without changing the fundamental SAS protocol.
2Reliability
If multiple redundant data paths are provided between SVCs and PSD array, then data access reliability is improved, but system complexity increases
Solution Approach 1:
Multiple data paths are merged at the branching board level, where a single logical connection point distributes signals to multiple physical storage devices through different physical paths. This combining approach provides redundant data access paths while maintaining a simplified system architecture, as the branching board abstracts the complexity of multiple paths from the storage virtualization controllers.
3Measurement precision
If signal integrity enhancing devices are added to data paths, then signal quality is improved, but device complexity and cost increase
Solution Approach 1:
Signal integrity enhancing devices are positioned as intermediary components within the branching board architecture. These devices are strategically placed at critical signal transmission points to maintain signal quality over extended distances and through multiple connections, while the branching board itself manages the complexity of integrating these enhancement devices into the overall system.
Data Source
AI summary
Disclosed is a redundant storage virtualization subsystem (SVS) having branching functionality. The SVS comprises a first and a second storage virtualization controller (SVC) and a physical storage device (PSD) array. A first and a second data path are provided between the first SVC and the PSD array passing through a first and a second signal integrity enhancing device (SIED), respectively, and configured as a first pair of redundant data paths. A third and a fourth data path are provided between the second SVC and the PSD array passing through the second and the first SIED, respectively, and configured as a second pair of redundant data paths. In view of the PSD array, the first and fourth data paths form a third redundant data path pair for a PSD, and the third and second data paths form a fourth redundant data path pair for a PSD.