Dynamic Flow Control in Distributed Storage Systems

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Distributed storage systems face challenges in efficiently managing I/O requests due to node overload and unbalanced workload distribution, leading to increased operational latency and potential system instability.

Innovation Solution

The system employs a method where I/O requests are decomposed into internal commands and executed across multiple nodes, with bandwidth limiters dynamically adjusting based on latency metrics to manage concurrent requests and reconfigure node workloads, ensuring balanced processing paths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If I/O requests are decomposed and distributed across multiple nodes, then system throughput and processing speed are improved, but system complexity and coordination overhead increase

Engineering Contradiction:
ImproveI/O request processing speedVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments I/O requests into multiple internal commands that are distributed across different nodes in the storage system. Each node independently processes its assigned commands, enabling parallel execution and improving overall throughput while maintaining manageable complexity through clear division of labor

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements universal node structures where each node can function as a receiver, processor, and forwarder of commands. This multi-functionality allows flexible workload distribution and simplifies system management by using standardized node interfaces throughout the distributed system

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If bandwidth limiters are used to control concurrent requests, then system stability is improved, but processing throughput may be reduced

Engineering Contradiction:
Improvesystem stabilityVSAvoidprocessing throughput
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements dynamic bandwidth limiters that automatically adjust their constraints based on real-time system conditions such as node load, latency metrics, and queue depths. This dynamic adjustment allows the system to maintain stability under heavy load while maximizing throughput when resources are available, eliminating the need for fixed conservative limits

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs feedback mechanisms where nodes report latency metrics and load conditions back to the bandwidth limiter, which then adjusts its control parameters accordingly. This closed-loop control ensures system stability while adapting to changing workloads, preventing both overload and unnecessary throttling

Inventive Principle:
Principle #23Feedback

3Ease of operation

If latency metrics are collected from all nodes, then workload balancing is improved, but communication overhead and measurement complexity increase

Engineering Contradiction:
Improveworkload balancingVSAvoidmeasurement complexity
Core Design Contradiction:
Ease of operationVSDifficulty of detecting and measuring

Solution Approach 1:

The patent extracts only the essential latency metrics needed for workload balancing decisions from the complex node operation data. By focusing on key performance indicators such as command execution time and queue depth rather than collecting all possible node statistics, the system achieves effective workload balancing with minimal measurement overhead

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces intermediary aggregation logic that collects and processes latency metrics from multiple nodes, transforming raw measurements into balanced workload decisions. This intermediary layer simplifies the measurement complexity by handling metric aggregation and interpretation centrally or semi-centrally, reducing the burden on individual nodes

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS11099753B2Method and apparatus for dynamic flow control in distributed storage systems
Publication Date: 2021.08.24 EMC IP HLDG CO LLC
  • US11099753B2 patent drawing
  • US11099753B2 patent drawing
  • US11099753B2 patent drawing

AI summary

A method for processing I/O requests that are received at a distributed storage system including a plurality of receiver nodes, a plurality of first nodes, and a plurality of second nodes, the method comprising: receiving, at a receiver node, an I/O request and executing the I/O request by using at least one of the first nodes and at least one of the second nodes; receiving, by the receiver node, one or more latency metrics from each of the first nodes and second nodes that are used to execute the I/O request, and reconfiguring the storage system, by the receiver node, based on any of the received latency metrics.