The Broadcom acquisition of VMware has dramatically changed the virtualization landscape, triggering an unprecedented migration wave toward open-source alternatives. This technical analysis explores all aspects of moving from VMware to Proxmox/KVM, with special focus on GPU workloads, security implications, and practical migration strategies.
Broadcom's VMware Takeover: The Catalyst for Mass Migration
Broadcom completed its $69 billion VMware acquisition in November 2023, and the impact has been far more disruptive than most expected. Three key changes have driven customers to explore alternatives:
- 72-core minimum licensing requirements implemented in April 2025 force organizations to license significantly more cores than they actually use. Previously, VMware required a minimum of 16 cores per CPU socket; now the minimum is 72 cores per product line regardless of actual usage. For smaller deployments, this creates substantial over-provisioning costs.
- Forced bundle purchases have replaced VMware's flexible product catalog. Broadcom consolidated VMware's 168+ products into just four main offerings: VMware Cloud Foundation (VCF), VMware vSphere Foundation (VVF), VMware vSphere Standard (VVS), and VMware vSphere Enterprise Plus (VSEP). This forces customers to purchase bundled solutions including components they don't need.
- Cease-and-desist notices for patch rollbacks began appearing in May 2025. Broadcom is sending legal notices to perpetual license holders whose support contracts expired, demanding they stop using any maintenance releases or patches installed after support expiration. This creates significant security risks by forcing customers to revert to vulnerable versions.
The financial impact has been staggering. Organizations report price increases of 300-1,250% when mapping their VMware usage to Broadcom's new bundled packages. This has triggered widespread migrations, with notable examples including Toshiba (after 16 years as a VMware customer) and MSIG Insurance Asia (moving 1,500-2,000 VMs to alternatives).
Cost Comparison: The Financial Case for Migration
For a typical mid-sized deployment (5 dual-socket servers, 16 cores per CPU), the cost differences are substantial:
VMware under Broadcom:
- Minimum license requirement: 72 cores per product line
- Approximate annual cost: $30,000-70,000+ depending on bundle
- Three-year commitment: $90,000-210,000+
- Additional costs for vSAN storage beyond included capacity
Proxmox/KVM:
- 5 servers with Basic subscription: ~$650/year
- 5 servers with Premium subscription: ~$2,000/year
- No core-based minimums or mandatory bundles
- No three-year commitment requirement
5-Year TCO Comparison:
- VMware: $150,000-350,000+ (depending on bundle)
- Proxmox: $3,250-10,000 (depending on support level)
For many organizations, potential savings of 90% or more make the migration effort financially compelling, even accounting for transition costs and potential feature gaps.
Performance Comparison: NVMe-TCP and GPU Workloads
NVMe-TCP Performance Advantage
Proxmox/KVM demonstrates superior NVMe-TCP storage performance compared to VMware ESXi:
- IOPS Performance: Proxmox outperforms VMware in 56 of 57 benchmark tests, delivering nearly 50% higher IOPS
- Latency: Over 30% lower latency while simultaneously delivering higher IOPS
- Bandwidth: 38% higher bandwidth during peak load conditions (12.8GB/s vs. 9.3GB/s)
This performance difference stems from architectural differences in I/O handling:
- Proxmox/KVM uses virtio-scsi with native Linux block devices, bypassing intermediate filesystem layers. The I/O path is more direct, with Linux's no-op scheduler for NVMe devices allowing more efficient handling of concurrent I/O operations.
- VMware ESXi employs a more complex I/O path with multiple layers, including VMFS, I/O scheduling, and a centralized scheduler that can become a bottleneck.
GPU Performance for AI Workloads
GPU performance varies by configuration and usage pattern:
- GPU Passthrough: Both platforms deliver near-native performance (98-100% of bare metal) with GPU passthrough. Proxmox shows minimal overhead (<1% difference) compared to native performance in most benchmarks.
- vGPU Performance: Performance drops when splitting GPU resources across VMs. VMware has a more mature vGPU implementation, but Proxmox 8.4 now offers comparable functionality.
Security Benefits: A Tale of Two Architectures
Recent VMware vulnerabilities highlight important security differences between the platforms:
Recent VMware ESXi Zero-Day Vulnerabilities
In March 2025, three critical vulnerabilities were disclosed:
- CVE-2025-22224: Critical severity (CVSS 9.3) TOCTOU vulnerability in VMCI allowing code execution
- CVE-2025-22225: High severity (CVSS 8.2) arbitrary write vulnerability enabling kernel writes
- CVE-2025-22226: Medium severity (CVSS 7.1) information disclosure in HGFS
When chained together, these vulnerabilities allow complete VM escape. An attacker with admin privileges in a guest VM could exploit these vulnerabilities to gain control of the host system. Approximately 409,000 potentially vulnerable targets were identified, with high exposure in China, France, and the United States.
Architectural Security Differences
VMware ESXi Architecture:
- Proprietary, closed-source with approximately 60 million lines of code
- Single hypervisor model with tightly integrated components
- VMX process (VM Runtime) is the primary attack surface
- Newer versions include sandbox features to contain VM escapes
Proxmox/KVM Architecture:
- Open-source KVM is part of the Linux kernel with significantly fewer lines of code
- Modular architecture separating kernel (KVM) and userspace (QEMU) components
- Attack surface divided between kernel module and userspace
- Newer implementations may use Rust for memory-safety improvements
Patching Flexibility Comparison
Proxmox/KVM offers more flexible patching due to its Linux foundation:
- Based on Debian with standard apt-based package management
- Security updates applied more flexibly using standard Linux tools
- Daily package update checks with administrator notifications
- Third-party solutions like TuxCare offer live patching without downtime
- Community security fixes can be implemented quickly
This contrasts with VMware's structured, vendor-controlled patching that now includes aggressive enforcement of support contracts and restrictions on patches for customers without current support.
NVIDIA vGPU Support in Proxmox 8.4
One of the biggest enterprise features previously missing from Proxmox was proper NVIDIA vGPU support, but Proxmox 8.4 (released April 2025) has changed that:
Official vGPU Implementation
- Proxmox VE became an officially supported platform for NVIDIA vGPU as of March 2025
- Support starts with NVIDIA vGPU Software version 18.0
- Includes helper utilities that streamline setup and configuration
Live Migration Capabilities
Live migration of VMs with NVIDIA vGPU is now supported in Proxmox 8.4:
- Both source and destination nodes must have identical GPU hardware and driver versions
- Migration takes longer than regular VM migration (approximately 5 minutes for a VM with 1GB RAM and 1GB vRAM)
- Automatic cleanup of the mediated device on the source host after successful migration
GPU Hardware Compatibility
For specific hardware configurations:
- NVIDIA L4 (24GB): Fully supported in Proxmox 8.4 with drivers version 550.90.05 or newer
- Tesla T4 (16GB): Fully supported for vGPU operations
- RTX A4000 (16GB): Works well for direct passthrough, but has mixed support for vGPU
Configuration Requirements
Host system requirements for NVIDIA vGPU on Proxmox 8.4:
- IOMMU support (VT-d for Intel or AMD-Vi for AMD) enabled in BIOS/UEFI
- SR-IOV support (especially important for Ampere and newer GPUs)
- Above 4G decoding enabled
- ARI (Alternative Routing ID Interpretation) for newer GPUs
- Compatible kernel version (6.8.12-10-pve or newer recommended)
- Latest stable NVIDIA vGPU drivers (570.133.10 for vGPU Software 18.1)
virt-v2v: Converting VMs from VMware to KVM
The virt-v2v tool provides a streamlined process for converting VMs from VMware to KVM. Here's a simplified approach:
Basic Conversion Process
Install required packages:
# On Debian/Ubuntu apt install -y qemu-kvm libvirt-daemon-system virt-manager virt-v2v
Prepare the source VM:
- Ensure VM is fully shut down (not hibernated/suspended)
- Remove VMware Tools
- For Windows VMs, ensure virtio drivers are available
Run the conversion:
# From VMware vCenter virt-v2v -ic vpx://username@vcenter.example.com/Datacenter/esxi "vmname" # From OVA file virt-v2v -i ova /path/to/vm.ova -o libvirt -of qcow2 -os storage_pool_name
Post-conversion steps:
- Update network configuration if needed
- Install optimized drivers
- Test VM functionality
Special Considerations for GPU Workloads
Converting VMs with GPU dependencies requires additional steps:
- Convert the VM without GPU configuration initially
- Boot once without GPU to ensure basic functionality
- Add GPU passthrough or vGPU configuration after successful boot
- Install appropriate drivers for the new environment
For NVIDIA vGPU:
- Document vGPU profile used in VMware
- Create equivalent mediated device in Proxmox
- Install matching NVIDIA GRID driver version in guest
- Reconfigure license server settings
Optimizing the Conversion Process
To minimize downtime during conversion:
- Conduct test conversions with clones of production VMs
- Use shared storage accessible by both VMware and KVM when possible
- Pre-install virtio drivers in Windows VMs before conversion
- Convert multiple VMs simultaneously if resources permit
- Prepare validation checklists to quickly verify functionality
VMware VCF 9 vs. Proxmox/KVM: Feature Comparison
While Proxmox/KVM provides compelling cost benefits, organizations should understand the feature differences:
Enterprise Features
| Feature | VMware VCF 9 | Proxmox/KVM |
|---|---|---|
| Live Migration | Full support including GPU | Supported, including GPU with Proxmox 8.4+ |
| Storage vMotion | Full support | Supported via different mechanism |
| High Availability | Fully automated with vSphere HA | Supported via HA cluster resources |
| Distributed Resource Scheduler | Advanced workload balancing | Basic automated resource distribution |
| VM Templates | Advanced templating and customization | Template and clone support |
| GPU Virtualization | Full vGPU support | Full support since v8.4 |
| Enterprise Support | 24/7 global support | Premium subscription support |
Hardware Compatibility Analysis
HPE DL360 Gen10 with NVIDIA L4 24GB GPU
- VMware: Fully compatible with VMware vSphere 8.x
- Proxmox: Compatible with Proxmox VE 8.x
- Considerations: May require IOMMU grouping adjustments for optimal GPU performance in Proxmox
- Workload suitability: Excellent for vLLM/BERT-Large inference with 24GB VRAM providing sufficient capacity for medium-sized models
HPE DL380p Gen8 with Tesla T4 16GB
- VMware: Compatible with vSphere 7.x (check 8.x compatibility)
- Proxmox: Compatible but requires specific configurations
- Considerations: Older server generation may need BIOS updates for proper IOMMU support
- Workload suitability: Good for inference workloads, but 16GB VRAM may limit larger models
Dell Precision Tower with RTX A4000 16GB
- VMware: Compatible but not officially supported for enterprise use
- Proxmox: Good compatibility, common configuration in community
- Considerations: May encounter the "Error 43" with NVIDIA driver which requires specific workarounds
- Workload suitability: Strong performance for AI workloads, professional-grade GPU with good stability
Monitoring with Prometheus and DCGM Exporter
For monitoring GPU performance in AI workloads:
Proxmox/KVM Implementation
- DCGM exporter integrates well with Proxmox's Prometheus support
- Can be deployed as a container or directly on host
- Monitors GPU usage, memory, temperature, and utilization
- Custom Grafana dashboards provide comprehensive visualization
- Supports advanced metrics like Tensor Core utilization
Implementation Steps:
- Install NVIDIA GPU drivers and NVIDIA Container Toolkit
- Deploy DCGM exporter (either as container or package)
- Configure Prometheus to scrape DCGM metrics
- Set up Grafana dashboards for visualization
Performance Optimization Strategies
Proxmox/KVM Optimization
Storage Optimization:
- Use virtio-scsi controllers instead of virtio block
- Enable aio=native and io_uring for improved I/O performance
- Configure iothreads for CPU-intensive storage workloads
GPU Optimization:
- Set CPU type to host for near-native performance
- Add iommu=pt to GRUB parameters for IOMMU passthrough mode
- For NVIDIA GPUs, add the x-vga=1 parameter for proper initialization
AI/ML Workload Optimization:
- Allocate sufficient memory for vLLM and other AI workloads
- Configure appropriate max_model_len and max_num_batched_tokens parameters
- For multi-GPU setups, properly configure tensor parallelism with tensor_parallel_size
Conclusion: Is Migration Right for You?
The decision to migrate from VMware to Proxmox/KVM depends on your specific requirements and constraints:
Reasons to Migrate:
- Dramatic cost savings: 90%+ reduction in virtualization licensing costs
- Freedom from forced bundles: Use only what you need
- Performance advantages: Better NVMe-TCP performance, comparable GPU performance
- Patching flexibility: Control your own security updates
- Open-source transparency: Community-driven development and security
Migration Challenges:
- Feature gaps: Missing some advanced enterprise features
- Operational changes: Different management paradigm
- Enterprise support: Relies more on community and optional commercial support
- Integration complexity: May require custom solutions for enterprise integration
The recent Broadcom changes have fundamentally altered VMware's position in the market, making Proxmox/KVM an increasingly attractive option even for enterprise environments. With proper planning and implementation, organizations can successfully migrate their virtualization infrastructure while maintaining performance for demanding workloads like GPU-accelerated AI applications.
For the specific workloads like vLLM/BERT-Large, Whisper, and Prometheus monitoring, Proxmox/KVM provides a capable platform with excellent performance characteristics when properly configured, offering a compelling alternative to increasingly expensive VMware deployments.
At Lazarus Labs, we've already helped several clients navigate this transition successfully. If you're considering a migration from VMware to Proxmox/KVM and need assistance evaluating your options or implementing a migration strategy, feel free to reach out.