Moving from VMware to Proxmox:
What You Need to Know

When Broadcom completed its acquisition of VMware in late 2023, the ripple effect was felt almost immediately across small and medium-sized businesses worldwide. Licensing structures were overhauled, perpetual licences were discontinued, and subscription costs surged — in some cases by hundreds of percent. For many SMBs, VMware had been the de-facto choice for virtualisation simply because it was what they knew. Now, for the first time, the maths forced a re-evaluation.

One of our clients, Antomix, a small professional services firm running a modest but business-critical infrastructure, found themselves staring down a renewal quote that made little sense for their scale. Three VMware ESXi hosts, twelve virtual machines, and an annual bill that was quietly becoming their single largest IT line item. They called Ridge for support.

Infrastructure: Before & After

Why Proxmox VE?

Proxmox Virtual Environment is a mature, enterprise-grade open-source hypervisor built on Debian Linux and KVM. It supports both full virtualisation (KVM) and container-based workloads (LXC), includes a polished web management interface, and ships with built-in clustering, high availability, live migration, and backup tools — all without requiring a separate management server or licence.

For this client, the decision rested on four factors:

• Cost: Community edition is free. Enterprise support subscriptions are optional and modest.
• Capability parity: Everything they were using in VMware — live migration, snapshots, storage management — exists natively in Proxmox.
• Operational familiarity: The web UI is intuitive, and Debian underpins the platform, meaning standard Linux tooling applies throughout.
• Exit freedom: No vendor dependency. The underlying VM disk format (qcow2 or raw) is portable and open.

Migration Roadmap — 4 Phases

Total elapsed time from kickoff to full decommission: approximately 5 weeks.

How We Achieved Zero Downtime

The key to a disruption-free migration is to never cut over until the destination is proven. Our approach ran VMware and Proxmox in parallel throughout the migration window, treating the ESXi infrastructure as the still-active source of truth until the very last moment.

• Export: Using qemu-img and VMware's VMDK-to-qcow2 conversion pipeline, we pulled a consistent snapshot of each VM's disk image.
• Import & configure: Each VM was imported into Proxmox with equivalent hardware configuration — CPU pinning, memory sizing, network interface mapping, and storage attachment.
• Shadow run: The Proxmox instance was booted, validated, and tested in an isolated VLAN before any production traffic was touched.
• Delta sync: For stateful workloads (particularly the database and mail server), we performed a second incremental sync immediately before cutover to minimise data lag.
• Atomic cutover: Network configuration (IP addresses, DNS entries) was updated in a coordinated change window, typically under five minutes per workload group.

Non-critical VMs — dev, staging, the test machine — were migrated first, allowing the team to refine the process and build confidence before touching production workloads. Production services followed in order of increasing criticality, with the database and mail server migrated last after the approach had been battle-tested across nine other VMs.

Annual Cost Comparison

The Results, One Month On

By the end of week five, all twelve VMs were running on Proxmox VE with no outstanding issues. The client's team completed a two-hour handover session covering day-to-day operations through the Proxmox web interface, and Ridge provided a written runbook covering backups, snapshots, adding new VMs, and basic troubleshooting.

What We'd Recommend

• Proxmox is a production-ready replacement for VMware ESXi in the SMB space. It handles the same workloads with less licensing complexity. If you have a smaller VM count, maybe consider a small Hyper-V setup instead.
• The migration effort is real but manageable. A 3-host, 12-VM environment like this one can be completed in under six weeks with proper planning.
• Zero downtime is achievable — but it requires discipline: parallel running, incremental syncs, and a tested rollback path for every workload.
• Factor in some investment in team training and documentation. Proxmox is intuitive, but it's different enough from vSphere to warrant a structured handover.

The migration project paid for itself in under five months. The client now runs a leaner, more flexible infrastructure — and they're not waiting anxiously for the next Broadcom announcement.