VMware VM migration typically includes cold and hot migration methods, with hot migration preferred for online businesses to ensure continuity. With Broadcom’s VMware pricing changes — Toshiba, a 16-year VMware user, decided to switch platforms after discovering that related product costs had increased by 10 times, migrating 2,200 VMs from VMware-Broadcom to alternatives.
The Importance of Hot Migration: The Cornerstone of Business Continuity
Hot migration seamlessly transfers VMs between physical hosts without interrupting business operations or services, contrasting with cold migration which requires shutdowns. Its core value is ensuring zero business downtime. It is essential for hardware upgrades, load balancing, system maintenance, and building highly available and resilient data centers.
Analysis of Core Technologies for Virtualization Hot Migration
Achieving zero-downtime migration requires integrating multiple complex technologies.
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Pre-Copy Based Memory Migration
The most common hot migration technology. The VM continues running while memory data is copied incrementally to the target host. The system tracks changed memory pages (dirty pages) and iteratively transfers only those.
Once dirty pages reach a small threshold, the virtual machine pauses for an extremely short time (at the millisecond level) to sync final pages, then resumes on the target host.
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Post-Copy Based Memory Migration
First transfers CPU and essential state to the target host, immediately starting the VM there. Memory not yet copied triggers page faults, and the target host then copies that memory page on demand from the source host.
This allows faster migration initiation but may cause more page fault interrupts during the early migration phase, causing temporary performance fluctuations.
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Shared Storage Hot Migration
Requires VM data disks on shared storage accessible to both source and target hosts. Only computational state (CPU and memory state) needs migration during hot migration, eliminating large storage data copies.
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Network-Assisted Hot Migration
Uses network optimization and intelligent scheduling — implementing data compression, deduplication, or priority control at the network level to reduce bandwidth consumption.
Intelligent scheduling algorithms select optimal migration paths based on host load and network conditions.
Hot Migration Practices
The ZSvirt virtualization platform provides a user experience consistent with VMware virtualization products, supporting intelligent unified operations and seamless V2V migration. Key features include:
- Simple:
Easy installation, intuitive interfaces for complex hot migration tasks, lowering technical barriers.
- Strong:
Robust architecture, HA between VMs and management nodes, with support for high-concurrency API requests.
- Scalable:
Supports elastic deployment from single services to 10,000+ servers with open APIs.
- Smart:
Automated operations, intelligent online upgrades, smart UI, real-time monitoring and auditing.
Disaster recovery solutions integrate with hot migration, supporting six major disaster recovery scenarios through technologies like snapshots, block data replication, and CDP.
Frequently Asked Questions
Q: What is hot migration? How is it different from cold migration?
A: Hot migration transfers VMs between hosts without interruption; cold migration requires the VM to be shut down before migration. The key advantage is achieving zero business downtime and ensuring service continuity.
Q: What role does hot migration play in enterprise data center operations?
A: Hot migration enables hardware maintenance, resource optimization, load balancing, failover, and system upgrades without affecting business operations.
During platform migrations like VMware-to-ZSvirt, it is one of the core technologies ensuring business continuity and data integrity.
Q: How does ZSvirt support hot migration functionality, and what are its advantages?
A: ZSvirt provides a VMware-consistent user experience with intelligent unified operations and seamless V2V migration capabilities, including live migration, cross-cluster/data center migration, and failure-driven migration.
Advantages include high stability, security, and ease of use.
Q: What are some best practice recommendations when performing VMware-to-ZSvirt hot migration?
A: Organizations should conduct a comprehensive environment assessment and migration plan before performing VMware-to-ZSvirt hot migration, ensuring network connectivity and storage compatibility.
It is recommended to leverage live migration capabilities together with real-time monitoring and verification to ensure a smooth and reliable migration process.