Asymmetric SAS Wide Link Bandwidth Reconfiguration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing information handling systems with SAS Expander Block Wide Links face inefficiencies due to asymmetrical read/write ratios, leading to underutilization of bandwidth, particularly with SSDs, where read performance outstrips write performance, resulting in congestion and suboptimal storage system response.
Innovation Solution
The system selectively re-configures narrow links within the SAS wide link to adjust bandwidth asymmetrically based on load direction, using a bi-directional link manager and load analyzer to reverse information flow and allocate bandwidth dynamically, ensuring balanced upstream and downstream communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If symmetrical bandwidth is provided through the wide link connector with four narrow links, then the link structure is simple and stable, but the bandwidth utilization is inefficient due to asymmetric read/write ratios
Solution Approach 1:
The patent implements dynamic link direction reversal where narrow links can switch between upstream and downstream directions based on real-time traffic patterns. The link manager monitors bandwidth utilization and dynamically reconfigures link directions to match asymmetric read/write ratios, transforming static symmetrical bandwidth into adaptive asymmetric bandwidth that optimizes productivity without permanent structural changes
Solution Approach 2:
The system changes the operational parameters of narrow links by reversing their communication directions. Instead of altering physical link structures, the patent modifies the logical direction parameters (upstream/downstream assignment) of existing links to align with actual traffic patterns, enabling efficient bandwidth utilization while maintaining the original simple link topology
2Power
If four narrow links are aggregated into a wide link connector, then the total bandwidth is increased, but congestion occurs when storage access patterns are asymmetric
Solution Approach 1:
The patent makes the wide link bandwidth allocation dynamic by allowing individual narrow links to reverse directions based on traffic demands. During read-intensive operations, more links are allocated to downstream direction, while write-intensive operations trigger upstream direction allocation, ensuring effective throughput matches actual workload patterns rather than remaining statically balanced
Solution Approach 2:
The patent segments the wide link bandwidth allocation by controlling each narrow link independently. Instead of treating the four links as a fixed unified resource, the system can selectively reverse individual link directions to create flexible bandwidth segments that match asymmetric access patterns, preventing congestion by distributing traffic more effectively across available paths
3Productivity
If the wide link connector supports asymmetric bandwidth allocation, then the storage system responds faster to asymmetric access patterns, but the link management complexity increases
Solution Approach 1:
The link manager implements self-service automation by autonomously monitoring bandwidth utilization patterns and automatically reversing link directions without external intervention. The system detects asymmetric access patterns and self-adjusts the link configuration to optimize performance, reducing the need for manual configuration while maintaining fast response times to changing workload conditions
Solution Approach 2:
The system employs feedback mechanisms where the link manager continuously monitors bandwidth utilization metrics and uses this information to make real-time decisions about link direction reversal. This closed-loop control enables the system to adapt to asymmetric access patterns dynamically, improving response time while managing complexity through automated feedback-driven adjustments rather than complex static configurations
Data Source
AI summary
A wide link communicates information between a storage enclosure having plural storage devices and an information handling system by selectively configuring upstream and downstream paths of narrow links to communicate in the same direction. A link load analyzer detects predetermined conditions, such as over utilization or under utilization of narrow link capacity, which initiates a re-configuration of the direction of information through a path of a narrow link. A master link manager configures a narrow link path to manage communication of configuration information for one or more narrow link paths configured to communicate in a direction.