VM Replication Throttling via Destination Write Rate Feedback

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Solution Overview

Problem

Virtual machine replication or migration can become unmanageable and fail to terminate within a reasonable time if not properly managed, particularly due to mismatched write rates between source and destination host computers.

Innovation Solution

Implementing a system that monitors and manages write rates by comparing the source and destination write rates, adjusting the source write rate to match or be less than the destination write rate, using a destination coefficient and slowdown control values to ensure synchronization and prevent overload.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the source VM writes operations log at high speed, then the replication speed is improved, but the destination VM cannot keep up causing incomplete migration

Engineering Contradiction:

Improvereplication speedVSAvoidmigration completion

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system continuously monitors the destination VM's write rate and feeds this information back to the source VM. The source VM adjusts its write rate based on this feedback to ensure the destination can keep up, thereby resolving the contradiction between high replication speed and complete migration.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The write rate is made dynamic rather than static. The source VM adjusts its write rate in real-time based on the destination's capacity, allowing the system to adapt to varying performance conditions and ensure both speed and completion.

Inventive Principle:

Principle #15Dynamics

2Productivity

If the destination VM writes to memory at limited speed, then the migration process is constrained, but increasing the source write rate creates a bottleneck

Engineering Contradiction:

Improvemigration throughputVSAvoidmigration duration

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The system allows the source VM to write at a rate that may exceed the destination's current capacity, but uses throttling mechanisms to ensure the destination doesn't overflow. This partial action approach allows aggressive replication when possible while preventing bottlenecks when necessary.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The system changes the write rate parameter dynamically based on destination capacity. When the destination can keep up, the source writes faster; when the destination is slow, the source throttles back, optimizing the overall migration duration.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the source VM throttles its write rate to match destination speed, then migration completion is ensured, but replication time is extended

Engineering Contradiction:

Improvemigration completionVSAvoidreplication duration

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The write rate is dynamically adjusted during the migration process. The system starts with higher rates when possible and throttles only when necessary, optimizing the balance between completion assurance and time efficiency.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system performs preliminary synchronization and uses destination write rate information to pre-adjust the source write rate, preventing throttling delays from extending the overall migration time unnecessarily.

Inventive Principle:

Principle #10Preliminary action

4Manufacturing precision

If the system monitors and manages write rates continuously, then synchronization is improved, but system complexity increases

Engineering Contradiction:

Improvewrite rate synchronizationVSAvoidrate management system

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The continuous monitoring and feedback mechanism provides precise synchronization control with relatively simple implementation, as it relies on standard network communication and rate calculation rather than complex coordination protocols.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS9223607B2System for replicating or migrating virtual machine operations log by throttling guest write iOS based on destination throughput

Publication Date: 2015.12.29 MICROSOFT TECHNOLOGY LICENSING LLC

AI summary

This application describes a system and techniques for managing the replication, migration, or backing up of virtual machines (VM) operating on a computing device. The techniques include managing real time or near real replication or migration of VM operations logs between computing devices. The operations logs include information or data that would enable another VM to function or operate in the same manner as the VM that generated the operations logs. Techniques are presented herein to insure the replication or migration process of VMs is not open ended or indefinite. For example, the write rate of the source operations log is managed to insure the replication or migration of the source operations log to destination device terminates within a reasonable amount of time.