With VMware’s licensing and ownership changes under Broadcom, many organizations are reevaluating their virtualization platforms. In 2025, one of the fastest-growing trends is the migration from VMware ESXi to Proxmox VE 9, an open-source and enterprise-grade alternative built on KVM and LXC.

Migrating a few VMs is simple — but migrating hundreds or thousands of VMs efficiently requires planning, automation, and the right tools. This blog post explains how to perform large-scale VM migration from VMware ESXi 8.x or 7.x to Proxmox VE 9 with minimal downtime and maximum consistency.

Why Organizations Are Migrating to Proxmox VE 9

• No licensing costs – fully open source with enterprise support options

• Unified virtualization & container management – KVM, LXC, ZFS, and Ceph in one platform

• Automation-friendly – robust API, CLI, and Ansible/Terraform integration

• Enterprise-grade stability – high availability, clustering, and live migration support

These benefits make Proxmox VE 9 a powerful replacement for VMware ESXi in both enterprise and SMB environments.

Migration Overview

For large environments, the best method is the virt-v2v-based migration, supported by automation scripts for batch processing.

Step 1: Assessment & Planning

Before you move anything, take inventory and plan carefully.

1.1 Inventory Your VMs

Export a complete list of your VMware VMs using PowerCLI:

1.2 Check Compatibility

• Ensure all VMs use SCSI/SATA controllers and BIOS/UEFI compatible boot modes.

• Remove VMware Tools before export.

• Record OS versions for driver preparation (especially Windows).

1.3 Define Migration Strategy

• Production VMs: schedule during maintenance windows

• Non-critical VMs: batch migrate during testing

Step 2: Prepare Proxmox VE 9 Cluster

1. Install Proxmox VE 9 on target nodes with all security updates.

2. Configure networking, storage, and Proxmox Backup Server.

3. If using shared storage, set up Ceph, NFS, or iSCSI.

4. Install conversion tools:

   apt install qemu-utils libguestfs-tools virt-v2v

Step 3: Conversion and Import

Using virt-v2v (Recommended Method)

1. Export VM from ESXi

   ovftool vi://user@esxi-host/vm-name /tmp/vm-export/


2. Convert VM to Proxmox Format

   virt-v2v -i vmx /tmp/vm-export/vm.vmx -o local -os /var/lib/vz/images/


3. Import into Proxmox

   qm create 101 --name myvm --memory 4096 --cores 2 --net0 virtio,bridge=vmbr0
qm importdisk 101 /var/lib/vz/images/myvm.qcow2 local-lvm
qm set 101 --scsihw virtio-scsi-pci --scsi0 local-lvm:vm-101-disk-0 --boot order=scsi0


4. Install virtio Drivers

   • For Windows: mount virtio-win.iso before booting.

   • For Linux: most modern kernels include virtio by default.

Step 4: Automate for Large-Scale Migration

When migrating dozens or hundreds of VMs, scripting is key.

Here’s a simple automation loop:

You can enhance this with:

• Logging for tracking progress

• Error handling

• Integration with Proxmox API (pvesh create /nodes/.../qemu)

Step 5: Validation & Testing

Before decommissioning VMware:

1. Boot each migrated VM in Proxmox test cluster

2. Validate:

   • Network interfaces

   • Disk performance

   • Application services

3. Fix any missing drivers or IP mismatches

4. Once stable, power off VMware VMs

Common Migration Issues & Fixes

Bonus: Advanced Proxmox Migration Setup

For enterprise setups:

• Use Proxmox Backup Server (PBS) for incremental backups & restores

• Deploy Ceph storage for high availability

• Automate deployments with Ansible or Terraform

These tools streamline migration management and future scaling.

Summary

Migrating from VMware ESXi to Proxmox VE 9 in 2025 is a strategic move for organizations seeking open-source freedom, cost control, and infrastructure flexibility.

Key takeaways:

• Use virt-v2v for efficient and automated conversions

• Plan, script, and validate at every step

• Integrate PBS or Ceph for high performance

• Test thoroughly before decommissioning VMware

With careful planning and the right automation, Proxmox VE 9 can become your reliable, cost-effective foundation for the next generation of virtualization.

Planning or Running a Production Migration?

Whether migrating from VMware or expanding an existing cluster, real environments require validation, rollback strategy, and performance tuning.

We assist organizations before, during, and after migration.

See available support options: https://www.saturnme.com/proxmox-managed-services/