Virtual Disk Bandwidth Throttling for Latency Simulation

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Solution Overview

Problem

Cloud-based virtual disks often experience unpredictable service levels and unfair resource sharing due to differences in latency and throughput characteristics, leading to unsatisfactory user experiences and potential disruptions.

Innovation Solution

Implementing artificial throttling of virtual disk access by simulating the latency and throughput characteristics of physical hard disk drives, using a disk access quota system that replenishes over time and caps at a predetermined value, to ensure stable service levels and fair resource distribution among virtual machines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If virtual disks are provided with high-speed access to underlying physical storage devices, then throughput and productivity are improved, but latency characteristics become unpredictable and service levels become unfair among virtual machines

Engineering Contradiction:
Improvedisk access throughputVSAvoidservice level predictability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent introduces an intermediary layer between virtual machines and physical storage devices that simulates physical disk latency characteristics. This intermediary virtualizes the storage interface to enforce realistic latency behavior, ensuring predictable service levels while maintaining high underlying storage throughput capabilities.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system dynamically adjusts latency parameters for virtual disk access based on simulated physical disk characteristics. By modifying access timing parameters to match real physical disk behavior, the system ensures predictable latency patterns while allowing the underlying storage infrastructure to operate at optimal speeds.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If multiple virtual machines share the same physical storage devices, then resource utilization is improved, but resource sharing becomes unfair and disruptions occur

Engineering Contradiction:
Improvestorage resource utilizationVSAvoidresource sharing fairness
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The patent segments storage resource access by allocating dedicated virtual disks to each virtual machine, with each virtual disk emulating independent physical disk characteristics. This segmentation ensures that each virtual machine experiences isolated, predictable access patterns while the underlying physical storage resources are efficiently shared and utilized by all virtual machines.

Inventive Principle:
Principle #1Segmentation

3Reliability

If virtual disks emulate physical hard disk drive characteristics, then service level predictability is improved, but additional complexity is introduced in managing simulated latency and quotas

Engineering Contradiction:
Improvelatency predictabilityVSAvoidthrottling mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system creates simplified copies of physical disk latency characteristics through virtualization. Rather than implementing complex physical disk hardware, the patent uses software-based virtual disks that replicate essential latency and throughput behaviors, achieving predictability through manageable simulation rather than physical complexity.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP2758877B1Bandwidth throttling of virtual disks
Publication Date: 2019.06.05 GOOGLE LLC
  • EP2758877B1 patent drawingFigure 1
  • EP2758877B1 patent drawingFigure 2
  • EP2758877B1 patent drawingFigure 3

AI summary

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for managing resources in a computing system. For virtual hard disk drives supported by multiple physic hard disk drives over a network, artificial throttling of the disk access bandwidth is implemented, such that the resulting latency behavior of each virtual hard disk drive resembles the latency behavior of a corresponding physical hard disk drive emulated by the virtual hard disk drive. In various implementations, the artificial throttling simulates both characteristics of sequential access latencies and random access latencies on a physical hard drive.