Virtual Machine Snapshot via Asynchronous Memory Queuing

Solution Overview

Problem

Conventional methods for creating virtual machine snapshots often require interrupting active user sessions and de-initializing virtualization services, which adversely affect the end-user experience and system efficiency, especially in interactive environments.

Innovation Solution

The method involves using a host RAM buffer to queue virtual memory pages and asynchronously save them to disk, allowing snapshot creation without interrupting user sessions by write-protecting memory pages and queuing them for compression and storage, thereby minimizing disk I/O operations and maintaining system efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional snapshot creation methods are used, then a virtual machine snapshot can be created, but active user sessions are interrupted and system efficiency deteriorates

Engineering Contradiction:

Improvesnapshot creation capabilityVSAvoidsystem efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system performs preliminary actions by write-protecting memory pages before snapshot creation and queuing them in advance. This allows the snapshot to be created without interrupting user sessions, as the memory protection is established beforehand and the actual snapshot operation can proceed asynchronously.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A host RAM buffer is introduced as an intermediary to queue virtual memory pages during snapshot creation. This buffer acts as a mediator between the virtual machine memory and the disk storage, allowing snapshot operations to proceed without directly blocking user sessions while maintaining data integrity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If conventional snapshot creation methods are used, then a virtual machine snapshot can be created, but user experience deteriorates due to session interruptions

Engineering Contradiction:

Improvesnapshot creation capabilityVSAvoiduser experience

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The system performs preliminary actions by write-protecting memory pages before snapshot creation and queuing them in advance. This allows the snapshot to be created without interrupting user sessions, as the memory protection is established beforehand and the actual snapshot operation can proceed asynchronously.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A host RAM buffer is introduced as an intermediary to queue virtual memory pages during snapshot creation. This buffer acts as a mediator between the virtual machine memory and the disk storage, allowing snapshot operations to proceed without directly blocking user sessions while maintaining data integrity.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If memory pages are queued and saved asynchronously, then system efficiency is maintained, but device complexity increases

Engineering Contradiction:

Improvesystem efficiencyVSAvoidsnapshot creation mechanism

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The snapshot creation process is segmented into distinct phases: write-protection of memory pages, queuing in the host RAM buffer, compression, and asynchronous disk saving. This segmentation allows each phase to be optimized independently and maintains system efficiency while managing complexity through modular organization.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system maintains continuity of useful action by allowing user sessions to continue uninterrupted while snapshot operations proceed in the background. The asynchronous architecture ensures that snapshot creation does not block normal system operations, maintaining continuous productivity.

Inventive Principle:

Principle #20Continuity of useful action

Data Source

PatentUS12182437B1Creating virtual machine snapshots without interfering with active user sessions

Publication Date: 2024.12.31 PARALLELS INT GMBH

AI summary

Systems and methods for creating virtual machine snapshots. An example method comprises: receiving a request to create a snapshot of a virtual machine running on a host computer system; protecting from modification a plurality of virtual memory pages of the virtual machine; responsive to detecting an attempt to modify a virtual memory page of the plurality of memory pages, copying the virtual memory page to a queue residing in a random access memory (RAM) of the host computer system; making the virtual memory page writable; retrieving the virtual memory page from the queue; writing the virtual memory page to a disk of the host computer system; and responsive to exhausting the queue, completing creation of the snapshot of the virtual machine.