How long does a VMware to Proxmox migration take?

It depends on the number of VMs, the size of the disks and the windows available. An SME with a dozen machines is typically migrated over a few scheduled sessions spread across several weeks, working in phases. Converting the larger disks is the single biggest factor in the timeline.

Does the migration cause service downtime?

For non-critical services, downtime is limited to the minutes needed to shut down and restart the VM. For critical workloads we use a scheduled out-of-hours cutover, with the original VM ready for rollback: the downtime users perceive is zero or a few minutes at most.

Can I migrate Windows VMs to Proxmox?

Yes. Windows guests migrate correctly once you install the VirtIO drivers for disk and network and remove the VMware Tools. This is the single most important step for achieving full performance and avoiding boot errors on the new hypervisor.

What happens to my Veeam backups after the migration?

Third-party backup tools are extending their support for Proxmox, but compatibility must be checked against the specific version. As an alternative, Proxmox Backup Server offers native incremental backups with deduplication. During the assessment we define the strategy best suited to your environment and your RTO and RPO targets.

Do I need to buy new hardware to move to Proxmox?

Not necessarily. Proxmox runs on the same servers, but setting up one or more parallel nodes — even temporary ones — lets you test the new environment without touching production. We assess case by case whether to reuse the existing hardware or add new machines alongside it.

Migrate from VMware to Proxmox

To migrate from VMware to Proxmox you build a parallel Proxmox VE cluster, export each virtual machine, convert the disks from VMDK to the KVM format and import them into the new environment. The migration runs in phases, starting with the least critical services, backed by full backups and an out-of-hours cutover that keeps downtime close to zero.

In more than 25 years as a B2B system integrator, TN Solutions has moved dozens of infrastructures from vSphere to Proxmox for small and mid-sized businesses. Since the Broadcom subscription hikes, it is the request we hear most often. This guide sets out the method we use in production: prerequisites, a step-by-step procedure, risk management and final testing.

Why Migrate from VMware to Proxmox

The main driver is cost. After the Broadcom acquisition, VMware scrapped perpetual licences and its SME bundles, moving to per-physical-core subscriptions with enforced minimums per CPU. Many companies saw double- or triple-digit percentage increases for exactly the same hardware.

Proxmox VE removes the licensing cost altogether: the software is open source and fully functional, with an optional per-socket support subscription that costs an order of magnitude less. On top of that it natively bundles clustering, high availability, backup through Proxmox Backup Server and LXC containers, with no separate paid modules.

Migration is not only about price, though. If you first want to work out whether Proxmox fits your workloads, read our comparison Proxmox vs VMware: which one to choose. Here we take that decision as made and focus on how to carry out the move safely.

Prerequisites: What to Check Before Migrating

A successful migration is won or lost in the assessment phase. Before we touch a single VM, we build a complete picture of the existing environment.

Inventory of the VMware Environment

You need an accurate census of everything running on vSphere:

number of ESXi hosts, their version and resources (CPU, RAM, storage);
a list of the VMs with their operating system, disks, vCPUs and assigned RAM;
application dependencies between VMs (databases, application servers, network services);
the maintenance windows available for each service;
current backup policies and RTO and RPO targets.

Target Hardware and Storage

Proxmox can run on the same servers, but it rarely makes sense to wipe the source environment before the new one has been tested. The safest approach is to set up one or more Proxmox nodes in parallel — temporary if need be — to import and test the VMs before the final switch.

Beneath the hypervisor, a solid foundation always matters: correct RAID configurations and redundant power supplies remain prerequisites whatever the platform. We have written a dedicated guide on choosing the right RAID level, which is useful for sizing the storage of the new cluster (RAID 1 or RAID 10 for transactional workloads, with a dedicated controller).

Guest Operating System Compatibility

Most Windows and Linux systems migrate without trouble, but two technical steps are essential:

remove the VMware Tools from the guest before or immediately after import, to avoid conflicts;
install the VirtIO drivers (disk and network) on Windows guests, so you get full performance on Proxmox. For Windows systems it pays to add the VirtIO driver before shutdown, to prevent boot errors on the new hypervisor.

How to Migrate from VMware to Proxmox Step by Step

Here is the operational flow we follow in production. The order is designed to reduce risk and keep a rollback path open at every stage.

1. Prepare the Proxmox Cluster

Install Proxmox VE on the target nodes and, if you need high availability and live VM migration, create the cluster by joining the hosts. Configure the storage (ZFS, Ceph, NFS or iSCSI depending on the architecture), the virtual networks (bridges and VLANs) that mirror the vSphere setup, and backups with Proxmox Backup Server.

2. Full Backup of the Source Environment

Before any conversion, take a full backup of the VMs on VMware. This is the safety net that makes every step reversible: if something does not add up, you restore the previous state with no data loss.

3. Export and Convert the Disks

Each VM is powered off (for a consistent copy) and exported. The virtual disks in VMDK format are converted to the format managed by KVM/QEMU (raw or qcow2). Proxmox provides native tools that, in recent versions, let you import VMs directly from an ESXi host or vCenter attached as external storage, which simplifies the conversion considerably.

For the larger disks, conversion takes time and bandwidth: schedule it in the right windows and avoid saturating the production network.

4. Create the VM on Proxmox and Reattach the Disks

On the new hypervisor, create a VM with equivalent resources (vCPUs, RAM, a BIOS/UEFI type that matches the original) and attach the converted disks. This is where you apply the VirtIO controllers and the network settings defined during the assessment.

5. First Boot and Verification

Start the VM on Proxmox in an isolated or test network, check the boot, install or finish the VirtIO drivers, and verify IP addresses, application services and connectivity. Only once the service responds correctly do you move on.

6. Controlled Cutover

For non-critical services the cutover is immediate: you shut down the VM on VMware and bring up the one on Proxmox. For critical services you use a scheduled out-of-hours cutover, keeping the original VM ready to restart until the new environment is 100% validated. This keeps perceived downtime at zero or a matter of minutes.

7. Testing and Decommissioning

After the switch, monitor performance and logs for a few days. Once stability is confirmed, decommission the original VMs and, gradually, the VMware licences you no longer need.

Managing the Risks: Backup, Rollback and Critical Services

The most common risk is not technical but organisational: underestimating application dependencies. Migrating an application server without its database, or reversing the start-up order, produces faults that are hard to diagnose. That is why the dependency map defined in the assessment is worth as much as the disk conversion itself.

Every phase is preceded by full backups that guarantee rollback: until final testing is signed off, the VMware environment remains the source of truth. The strategy should be designed around clear RTO and RPO targets, in line with our approach to server virtualisation and disaster recovery, not improvised on the day.

A word on compliance: for companies within the scope of the NIS2 directive, the choice of hypervisor and the robustness of recovery procedures form part of the risk-management obligations. Documenting the architecture, the redundancies and the migration plan is no longer optional.

Running VMware and Proxmox Side by Side During the Transition

You do not have to migrate everything at once. The most prudent strategy for many SMEs is hybrid and gradual: keep VMware for workloads tied to vendor certifications or contracts, and move everything else to Proxmox. Licence counts drop straight away, without exposing critical services to needless risk. Once validation is complete, you finish moving the remaining workloads too.

Why Choose TN Solutions

TN Solutions is a B2B system integrator with more than 25 years of experience, based in Melzo, near Milan. We are certified to ISO 9001 for quality and ISO 27001 for information security: design, migration and data management follow verified procedures.

We run the project end to end — assessment, sizing of the new cluster, conversion, cutover and testing — with a single point of contact for infrastructure, server virtualisation and support. Our 37 Google reviews with a 4.7 rating reflect a hands-on approach focused on business continuity. We do not switch off your production line to experiment: we work in parallel and move to the new environment only once it is verified.

Let's Talk About Your Migration

Would you like a tailored VMware-to-Proxmox migration plan, with defined timelines, costs and intervention windows? Our experienced engineers analyse your infrastructure and propose a path with no service downtime and guaranteed rollback.

Call TN Solutions on 02 9517550 or reach us through our contact page to request a no-obligation assessment.

During and after cutover, our system support service manages configuration, storage and networking on the new cluster, while our dedicated Proxmox backup should be switched on from day one on the new environment, well before the VMware VMs are ever powered off.

How to Migrate from VMware to Proxmox: A Practical Guide for SMEs

Why Migrate from VMware to Proxmox