Hypervisor Virtual Machine Memory Mapping for Fast Host Upgrade
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Solution Overview
Problem
Live migration of virtual machines during host upgrades is time-consuming and computationally expensive, requiring either restarting the virtual machines or migrating them to another host, which can disrupt uptime and is resource-intensive.
Innovation Solution
The hypervisor maps virtual machine memory to persistent storage, synchronizes changed data, pauses the virtual machine before host restarts, saves and restores the virtual machine state, and resumes operation after restarts, eliminating the need for special hardware like persistent memory cards with power sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If live migration is performed to upgrade hosts, then host software can be upgraded, but the process becomes time-consuming and computationally expensive
Solution Approach 1:
The hypervisor pre-synchronizes virtual machine memory to persistent storage before the host restart is initiated. By detecting the restart request in advance and copying changed memory pages to persistent storage beforehand, the system prepares the VM state in advance, enabling rapid resume after host upgrade without time-consuming live migration during the actual upgrade process.
2Adaptability or versatility
If live migration is performed to upgrade hosts, then host software can be upgraded, but computational resources are heavily consumed
Solution Approach 1:
The invention extracts the memory persistence requirement from the host system by mapping virtual machine memory directly to persistent storage with its own power source. This separation allows the host to be upgraded or restarted without migrating the VM, as the VM state is maintained independently in persistent storage, eliminating the computationally expensive live migration process entirely.
3Reliability
If virtual machine memory is stored on persistent memory card with power source, then memory persistence during host crash is enabled, but specialized hardware requirements increase
Solution Approach 1:
The hypervisor implements a universal memory mapping mechanism that maps virtual machine memory to persistent storage through software configuration. This multi-functional approach allows the same persistent storage infrastructure to serve both as regular storage and as VM memory persistence medium, eliminating the need for specialized persistent memory cards with power sources while maintaining reliability.
Data Source
AI summary
A system includes at least one memory including a persistent storage, at least one processor in communication with the at least one memory, a virtual machine associated with a virtual machine memory, and a hypervisor executing on the at least one processor. The hypervisor is configured to map the virtual machine memory to the persistent storage, detect a request to restart a host, and synchronize the virtual machine memory by copying data to the persistent storage for each page of the virtual machine memory that has changed. The hypervisor is also configured to pause the virtual machine prior to the host restarting, save a virtual machine state to the persistent storage, restore the virtual machine state after the host restarts, and resume operation of the virtual machine.