Broadcom’s VMware licensing changes have pushed a lot of organisations to look for alternatives. This guide is part of our comprehensive look at the VMware migration wave, where we explore the strategic and technical challenges organisations face when transitioning away from VMware. But here’s what happens too often – a vendor promises you can migrate in 6 months, management signs off on an aggressive timeline, and twelve months later you’re still untangling dependencies while paying for both platforms.
The reality doesn’t match the sales pitch. If you’re managing 50-500 VMs, you’re looking at 6-12 months if you’re focused and methodical. Got 500+ VMs? You’re in for 18-48 months depending on how complex your environment is and how big your team is.
This guide walks you through realistic timeline planning, migration tool selection, and a phase-by-phase execution strategy. You’ll learn how to choose between Nutanix Move, Azure Migrate, and Proxmox Import Wizard, how to structure your proof-of-concept, and how to avoid the pitfalls that extend migrations by months.
The goal is simple – build a migration plan that balances speed with risk mitigation, not one that looks impressive in a presentation but falls apart when you hit production.
How Long Does It Take to Migrate from VMware to Proxmox?
For 50-500 VMs, expect 6-12 months with a focused approach. Enterprise migrations with 500+ VMs? You’re typically looking at 18-48 months depending on application complexity and how many people you can dedicate to it.
Break this down into phases. Assessment takes 2-4 weeks, proof-of-concept runs 2-4 weeks, pilot migration spans 4-8 weeks, and bulk migration varies based on how many waves you’re running.
Several factors affect your timeline. VM count matters, but application complexity often matters more. Legacy applications with undocumented dependencies can add months. Team skills play a big role – if your team lacks platform experience you’re facing training time and a longer learning curve. Understanding the broader context of why organisations are migrating helps justify realistic timelines to stakeholders.
Available downtime windows constrain speed. Narrow maintenance windows every few weeks prevent aggressive migration waves. Your chosen migration approach impacts timeline too – agentless tools like Nutanix Move speed things up compared to manual conversions.
Here’s what extends timelines: complex dependencies that weren’t mapped properly, limited team capacity forcing smaller waves, restrictive downtime windows, and legacy applications requiring special handling.
What accelerates timelines: simple, well-documented workloads, agentless migration tools, a dedicated migration team that isn’t being pulled into other priorities, and flexible scheduling.
One financial services provider decided on a two-year subscription to buy time while running a structured RFP process. That’s realistic planning that acknowledges migration complexity.
The Gartner analyst Paul Delory put it bluntly: “There is no like-for-like replacement for the VMware hypervisor on the market.” Migration represents a strategic shift that needs proper planning and validation.
What Are the Main Phases of a VMware Migration Project?
Migration isn’t a single event. It’s a structured process with five distinct phases, each with specific acceptance criteria.
Phase 1 – Assessment involves taking stock of your current environment. Document VM configurations including vCPU count, memory, disk size, and NIC settings. Identify dependencies between applications and classify VMs by complexity. This phase takes 2-4 weeks and produces a detailed migration scope.
Phase 2 – Proof-of-Concept tests migration tools and processes on 3-10 representative VMs over 2-4 weeks. Pick a simple workload, a medium complexity application, and something challenging. The POC validates your tool choice, exposes hidden challenges, and gives your team hands-on experience before production pressure hits.
Phase 3 – Pilot Migration is your first production wave, typically 20-50 VMs. This validates your full migration process at modest scale. You’re testing coordination between teams, verifying validation procedures, and identifying process gaps that didn’t surface in the POC. The pilot usually runs 4-8 weeks including post-migration validation time.
Phase 4 – Bulk Migration organises remaining VMs into waves based on dependency mapping and business priorities. Wave size depends on team capacity – typically 20-100 VMs per wave. Start with non-critical systems, build confidence, tackle complex dependencies later. Consider compliance requirements when scheduling waves since regulated workloads need additional validation time.
Phase 5 – Decommissioning retires old VMware infrastructure after a validation period. Don’t rush this. Keep source VMs available for several weeks so you can roll back if needed.
Each phase has decision gates. Before moving from POC to pilot, validate that your migration process works, your team is trained, and you’ve documented procedures. Before bulk migration, confirm the pilot succeeded, stakeholders signed off, and you’ve refined processes based on what you learned from the pilot.
Common mistakes: skipping the POC to save time, rushing the pilot before procedures are solid, and inadequate validation between phases that allows issues to compound across waves.
How Do I Choose the Right Migration Tool for My Organisation?
Tool selection depends on five factors: destination platform, VM count, budget, team technical skills, and downtime tolerance.
Nutanix Move works best for migrations to Nutanix AHV. It’s free, agentless, and highly automated. Nutanix Move provides cross-hypervisor VM mobility with minimal downtime transitions. The limitation – it only targets Nutanix environments.
Azure Migrate is optimal for cloud migrations. It provides integrated assessment and migration, supports multiple source platforms, and ties naturally into Azure’s ecosystem. The requirement is Azure commitment – it’s designed for organisations moving to Microsoft’s cloud.
Proxmox Import Wizard is built into Proxmox VE. Released in late 2024, it gives Proxmox admins an official way to migrate VMware ESXi virtual machines. The wizard pulls across CPU and memory configuration and handles target storage mapping. It’s more manual than Nutanix Move but costs nothing beyond your Proxmox infrastructure. Good for straightforward migrations, less suitable for complex environments needing heavy automation.
Other options exist. StarWind V2V works for small-scale migrations but requires more manual work. Veeam leverages existing backup investments but comes at higher cost. Red Hat has a Migration Toolkit for Virtualization that can perform both cold and warm migrations.
Match tool capabilities to your specific requirements rather than chasing the “best” tool. A 50-VM migration to Proxmox has different needs than a 500-VM migration to Nutanix or a cloud migration to Azure. For a detailed comparison of these alternative platforms, see our comprehensive analysis of VMware alternatives including technical capabilities and enterprise readiness assessments.
Decision framework: If your destination is Nutanix and you want minimal manual work, use Nutanix Move. If your destination is Azure and you’re comfortable with cloud commitment, use Azure Migrate. If your destination is Proxmox and budget is tight, use the Import Wizard. For everything else, evaluate based on automation needs, scale, and integration with existing tools.
How Do I Plan and Execute a Proof-of-Concept Migration?
POC scope should include 3-10 VMs representing different complexity levels. Pick a simple workload, medium complexity application with a database, and something representing your toughest scenarios.
Duration runs 2-4 weeks including planning, execution, validation, and lessons learned documentation. Rushing the POC costs you months later when you discover tool limitations during production.
The POC validates that your tool selection works, tests migration processes, identifies hidden challenges, trains your team, and establishes baseline timing for estimating full migration duration.
Define success criteria before starting. What does success look like? All test VMs functional on the target platform? Migration procedures documented? Team confidence rating above a specific threshold? Define performance baselines in VMware ESXi including CPU, RAM, I/O, and network latency, then compare with the target environment.
POC deliverables include a validated migration runbook, timeline estimates based on measured performance, tool configuration documentation, and a lessons learned report.
Common POC mistakes: skipping validation testing, not documenting procedures, and declaring success prematurely.
Identify a non-critical application stack with 3-5 VMs as your first group. Obtain stakeholder sign-off from application owners and the security team before proceeding.
Start with internal, non-customer-facing projects to limit risk while you test your approach. POCs help identify potential challenges and refine requirements in a controlled environment before production pressure hits.
What Is Phased Migration and How Do I Plan Migration Waves?
Phased migration means breaking the full migration into multiple smaller waves rather than a “big bang” all-at-once approach.
The benefits are tangible. Failures affect smaller batches. You refine procedures between waves. Migration work spreads across weeks or months. This reduces risk and maintains business continuity.
Wave planning follows a process: map dependencies between VMs, group VMs by those dependencies, prioritise groups by business value, then schedule around available downtime windows. Budget planning affects wave size and timing since each wave requires resource allocation for migration tools, temporary infrastructure, and team effort.
Typical wave size runs 20-100 VMs depending on team capacity. Start conservative with smaller waves, expand as confidence grows.
Wave sequencing matters. Start with non-critical workloads, build confidence and refine procedures, then tackle complex dependencies in later waves.
Between-wave activities include validating that migrations succeeded, documenting lessons learned, adjusting procedures based on what worked and what didn’t, and training additional team members for later waves.
For legacy applications that require stacks of VMs to operate together, group VM migrations by application or service. Migrate the entire stack in one wave to maintain functionality.
Consider a hybrid integration layer if you’re repatriating workloads in stages and need public cloud and on-premises systems to communicate during migration.
How Do I Minimise Downtime During VMware Migration?
Two migration approaches exist: hot migration and cold migration.
Hot migration means live migration with minimal downtime – seconds to minutes. VMware HCX enables live migration of workloads with zero downtime, allowing businesses to transition applications without interrupting operations. The limitation is cross-platform support – not all target platforms support hot migration from VMware.
Cold migration requires VM shutdown. It’s more reliable for cross-platform migrations but needs approved downtime windows. Most VMware to Proxmox or Nutanix migrations use cold migration because it’s simpler and more predictable.
Downtime reduction strategies include migrating during maintenance windows, using a staged approach where you prepare everything before the final cutover, maintaining rollback capability to reverse failed migrations quickly, and rehearsing cutover procedures so the team executes smoothly under pressure.
Network pre-configuration helps. Set up networking on the target platform before migration day. When cutover happens, you’re just moving VMs, not also configuring networks and storage.
Cutover procedures need documentation – step-by-step processes for switching production traffic to migrated VMs. Don’t wing this. Document it, test it in the POC, refine it in the pilot.
Business communication matters. Coordinate with stakeholders about maintenance windows, set realistic expectations about duration and potential issues, and establish escalation procedures if things go wrong.
Use replication tools that allow incremental syncs so final cutover involves minimal downtime. The bulk of data transfer happens before the maintenance window, leaving only final synchronisation for cutover night. Red Hat’s Migration Toolkit for Virtualization handles both cold and warm migrations using this approach.
What Staff Training Is Needed for Migration Success?
Training timeline should start 2-3 months before POC to build foundational skills. Don’t wait until migration week to train your team.
Role-based training paths matter. Administrators need deep platform skills – installation, configuration, troubleshooting, performance tuning. Developers need API and automation knowledge for scripting and integration work. Managers need planning and oversight training to coordinate migration activities and make informed decisions.
Platform-specific requirements vary. Proxmox requires Linux and KVM knowledge – if your team only knows VMware’s Windows-based management, expect a learning curve. Nutanix has a different operational model focused on hyperconverged infrastructure. Hyper-V leverages existing Windows skills, making it easier for Windows-focused teams.
Hands-on lab time matters. Theoretical training alone doesn’t build confidence. Set up a lab environment before planning the migration to allow admins hands-on experience. This is where they make mistakes safely and learn workflows before production pressure hits.
Training duration estimates run 40-80 hours per administrator for new platform proficiency. Nearly 4 in 10 IT leaders cite lack of in-house expertise as a top barrier to repatriation. Don’t underestimate this.
Knowledge transfer approach: train a core team first, then cascade knowledge to the broader team during the pilot phase. The core team leads early waves, training others through hands-on work rather than classroom sessions.
Run targeted training for in-house teams months before migration, focusing on specific tools and architectures they’ll manage. Supplement internal staff with short-term contractors or managed services to cover expertise gaps. Pair external experts with internal staff in joint teams for knowledge transfer – this builds internal capability while getting expert guidance.
Proxmox.com offers instructor-led and on-demand courses covering clustering, storage, backups, and high availability. Use vendor training resources rather than piecing together YouTube tutorials.
How Do I Handle Failed Migrations and Plan Rollback Procedures?
Rollback planning starts before each wave begins. Define rollback criteria – what conditions trigger a rollback decision? Application not functioning properly? Performance degraded by more than 20%? Integration failures with dependent systems? Know these criteria before migration day. Security considerations should factor into rollback decisions, particularly if migrated systems introduce unexpected vulnerabilities or compliance gaps.
Technical rollback methods are straightforward: keep source VMs intact during the validation period, maintain network connectivity to the old environment so switching back is quick, and document the exact state before migration to enable accurate rollback.
Testing rollback procedures happens during POC and pilot. Don’t wait for a production disaster to discover your rollback process doesn’t work. Practice rollback so your team can execute under pressure.
Decision timeline matters. Establish how long you’ll monitor migrated VMs before declaring success and decommissioning source VMs. Two weeks minimum for non-critical systems, four weeks for business-critical applications. This validation period keeps your safety net in place.
Common failure scenarios include application compatibility issues that didn’t surface in testing, performance degradation despite matching resource allocation, integration failures with third-party systems, and data integrity problems discovered post-migration.
Documentation requirements: capture detailed state before migration – VM configurations, network settings, performance baselines, application versions. This enables accurate rollback if needed.
FAQ
What is V2V conversion and how does it work?
V2V (Virtual-to-Virtual) conversion transforms virtual machine disk formats and configurations from VMware’s platform to alternative hypervisors. The process extracts VM disk contents, converts formats (VMDK to QCOW2 or VHD), translates configuration settings, and reinstalls platform-specific guest tools. Nutanix Move and Azure Migrate automate this process, handling the technical complexity transparently.
Do I need to uninstall VMware Tools before migration?
VMware Tools should be uninstalled before migrating to avoid conflicts with the new hypervisor’s guest agent. Some migration tools handle VMware Tools removal automatically during conversion. Best practice: verify your specific migration tool’s recommendations, as procedures vary. For Proxmox migrations, manual removal before migration often produces better results. If you wait until after migration, you’ll receive errors when attempting uninstallation.
Can I migrate some VMs and keep others on VMware?
Yes, hybrid approaches are common during phased migrations. Many organisations keep critical legacy applications on VMware while migrating less complex workloads first. This strategy allows risk reduction and learning before tackling complex systems. However, maintaining dual platforms increases operational complexity and licensing costs during the transition period. Parallel operation during transition periods is standard practice for organisations taking incremental approaches.
How do I validate that migrated VMs work correctly?
Validation testing should include functional testing (applications start and operate normally), performance benchmarking (comparing metrics to source environment), integration testing (connectivity to databases, APIs, services), data integrity verification (checksums, data comparisons), and user acceptance testing for business-critical applications. Power on the VM, verify NIC connectivity, DNS resolution, time sync, and application responsiveness, then compare performance metrics to baseline and adjust resources if needed. Document validation procedures during POC and apply consistently to all migration waves.
What happens if my migration tool doesn’t support my source environment?
If your chosen tool lacks support for specific VMware features or configurations, consider manual conversion using tools like StarWind V2V, simplifying source VM configurations before migration, using intermediate conversion steps, or selecting alternative migration tools. Complex scenarios may require consulting expertise. The POC phase should expose these incompatibilities before committing to full migration. Test the wizard on non-critical VMs first to evaluate performance and spot unsupported hardware configurations.
How much will migration cost beyond just new platform licensing?
Total migration costs include new platform licensing, migration tool licensing if applicable, staff training (40-80 hours per admin at internal rates or external training costs), consultant fees if using managed services, potential hardware upgrades, extended VMware licensing during the transition period, and opportunity cost of staff time. Budget 1.5-3x the new platform licensing cost for the total migration programme. Organisations must factor in training for staff, potential downtime, tool replacement for monitoring and management systems, and support contracts. For a comprehensive breakdown of cost considerations including hidden expenses and ROI calculations, see our detailed TCO analysis.
Should I migrate to cloud or on-premises alternative?
Decision factors include current infrastructure investment, team cloud skills, application cloud-readiness, data sovereignty requirements, connectivity reliability, and long-term cost projections. Cloud migration (Azure, AWS) offers operational benefits but ongoing costs. On-premises alternatives (Proxmox, Nutanix) leverage existing infrastructure investments. Many organisations adopt hybrid approaches based on workload characteristics. Assess whether workloads require elastic scaling capabilities or benefit from more stable resource allocation found in on-premises environments.
How do I convince management to approve a realistic timeline?
Present evidence-based timeline estimates tied to organisation size and complexity. Show the risks of rushed migrations: failed cutovers, extended downtime, staff burnout, and ultimately longer timelines due to rework. Provide a phased approach with clear milestones and early success criteria. Compare internal timeline estimates to industry case studies. Position adequate timeline as risk management, not delay. Treat the VMware migration decision like Oracle – understand what you’re trying to achieve, evaluate total cost and risk, make choices based on business outcomes.
What are the most common migration mistakes to avoid?
Common pitfalls: inadequate assessment leading to timeline underestimation, skipping POC and discovering tool limitations too late, poor dependency mapping causing service outages, insufficient staff training resulting in operational issues, neglecting rollback planning leaving no safety net, inadequate downtime window planning forcing rushed cutovers, and declaring success before proper validation testing. Migration isn’t free – each alternative comes with trade-offs including learning curves, integration gaps, and performance variations.
Can I automate bulk VM migrations?
Yes, most modern migration tools support bulk operations and automation. However, automation works best for homogeneous environments with standard configurations. Complex VMs with unique networking, storage, or dependency requirements often need manual handling. Proxmox contains pvesh CLI and REST API for scripting VM imports. Combine with PowerShell or Bash to iterate over inventory lists and track job status. Best practice: automate the standard migration workflow you developed during POC, but maintain manual processes for exceptions. Automation reduces execution time but doesn’t eliminate planning needs.
How do I handle database servers during migration?
Database migrations require special consideration: longer downtime for large databases, data integrity verification is critical, replication setup for minimal downtime approaches, connection string updates for all dependent applications, and thorough performance testing post-migration. Consider migrating database servers in dedicated waves with extended validation periods. Application-level replication may enable lower downtime than VM-level migration. Test critical workflows in a staging environment to identify and resolve incompatibilities before production cutover.
What if my team lacks experience with the target platform?
Address skill gaps through formal training before POC (2-3 months lead time), hiring experienced staff or contractors for the migration phase, engaging consulting partners for knowledge transfer, extended POC period for team learning, starting with simple workloads while skills develop, and maintaining vendor support contracts. Skill development extends timeline but is critical for post-migration operational success.
