Introduction to Proxmox: Open-Source Virtualisation for Modern Infrastructure

The virtualisation landscape is shifting. With VMware licensing costs increasing significantly following the Broadcom acquisition, organisations are actively seeking alternatives that deliver enterprise features without the enterprise price tag.

Many technical decision-makers have heard of Proxmox but aren't sure what it actually is, what it can do, or whether it's suitable for their needs. This uncertainty is understandable - whilst Proxmox has powered millions of installations globally, it hasn't had the marketing budget of commercial alternatives.

This article provides a comprehensive introduction to Proxmox Virtual Environment, explaining what it is, how it works, and what it enables you to do. We'll cover the fundamentals from basic concepts to core capabilities, without assuming any prior knowledge. By the end, you'll understand whether Proxmox deserves a place in your infrastructure evaluation.

What is Proxmox VE?

Proxmox Virtual Environment (Proxmox VE) is an open-source server virtualisation platform that combines two virtualisation technologies - KVM for full virtual machines and LXC for lightweight containers - into a single, cohesive management interface.

Based on Debian Linux, a stable and well-supported operating system, Proxmox VE provides enterprise-grade virtualisation capabilities without the licensing costs associated with commercial alternatives. The entire platform is managed through a web browser interface, eliminating the need for separate management servers or complex client software installations.

Released under the GNU AGPL v3 licence, Proxmox VE is completely free to download, use, and modify. As of December 2025, the current version is 9.1.2^[src], with the development team at Proxmox Server Solutions GmbH maintaining regular updates and security patches.

The platform serves as a Type 1 hypervisor, meaning it runs directly on your server hardware rather than on top of another operating system. This direct hardware access delivers better performance compared to Type 2 hypervisors that run as applications within an existing OS.

Understanding Virtualisation

For readers less familiar with virtualisation concepts, here's a straightforward explanation: virtualisation allows you to run multiple independent operating systems on a single physical server. Each virtual machine (VM) acts as if it has its own dedicated hardware - CPU, memory, storage, and network connections - even though these resources are actually shared amongst multiple VMs.

Businesses virtualise for several compelling reasons. Hardware consolidation reduces the number of physical servers needed, cutting costs for equipment, power, cooling, and data centre space. Flexibility improves dramatically - you can create new servers in minutes rather than days, and move workloads between physical hosts without downtime. Resource efficiency increases as you can allocate exactly the CPU and memory each workload needs, avoiding the waste of underutilised physical servers.

Core Virtualisation Technologies

Proxmox VE's strength lies in supporting two distinct virtualisation approaches, each optimised for different use cases. Understanding when to use each technology helps you design efficient infrastructure.

KVM - Full Virtual Machines

Kernel-based Virtual Machine (KVM) is built directly into the Linux kernel, providing full hardware virtualisation. Each KVM virtual machine runs a complete operating system - Windows, Linux, BSD, or others - with its own virtualised hardware including CPU, RAM, storage controllers, and network interfaces.

KVM delivers near-native performance on modern processors with virtualisation extensions (Intel VT-x or AMD-V). This makes it suitable for running Windows applications in your Linux-based infrastructure, creating isolated environments for security-sensitive workloads, or testing different operating systems without dedicated hardware.

The performance overhead of KVM virtualisation is minimal on modern hardware. You're running real operating systems with real kernels, providing the strongest isolation between virtual machines - critical for multi-tenant environments or when running untrusted code.

LXC - Lightweight Containers

Linux Containers (LXC) take a different approach, sharing the host's Linux kernel rather than virtualising complete hardware. This dramatically reduces overhead - containers start in seconds rather than minutes, consume less memory, and deliver near-native performance for CPU and I/O operations.

LXC containers are ideal for running Linux-based services and applications where you don't need full OS isolation. Web servers, databases, application servers, and microservices all run efficiently in containers. Development and testing environments benefit from the speed of container creation and destruction.

The trade-off is flexibility - LXC containers can only run Linux distributions, and they share the host kernel. For workloads that need Windows or require the strongest isolation guarantees, KVM remains the appropriate choice.

The Web Management Interface

Proxmox VE's web interface runs on each node, accessible via HTTPS on port 8006. Unlike VMware vSphere, which requires a separate vCenter server for cluster management, Proxmox's management interface is built into every installation. This reduces complexity and eliminates a potential single point of failure.

The interface provides a single pane of glass for all virtualisation operations. You can create and manage VMs and containers, configure storage pools, set up networking including bridges and VLANs, schedule automated backups, monitor resource usage across your cluster, and manage user permissions and authentication - all from your web browser.

Role-based access control integrates with multiple authentication sources including local users, LDAP, Active Directory, and others. This makes it straightforward to implement the principle of least privilege, giving team members exactly the access they need.

Built-in console access means you can troubleshoot VMs and containers directly through the web interface, even when network connectivity fails. The noVNC-based console works in any modern browser without plugins or additional software.

Proxmox VE 9 introduced mobile-friendly interface improvements, making it practical to check system status or perform emergency operations from a phone or tablet. Whilst you wouldn't build infrastructure from a mobile device, being able to investigate alerts or perform basic operations remotely proves valuable.

Storage Capabilities

Proxmox VE takes an unopinionated approach to storage, supporting both local and network storage without artificial limitations on types or sizes. This flexibility allows you to choose storage technologies that match your requirements and budget.

Local Storage Options

ZFS provides enterprise-grade features including automatic data integrity checking, compression, and snapshots. The copy-on-write architecture makes ZFS excellent for virtualisation workloads, though it requires adequate RAM - plan for at least 1GB per TB of storage, more for production workloads.

LVM and LVM-Thin offer flexible volume management with snapshots and cloning. LVM-Thin adds thin provisioning, allowing you to overcommit storage - useful when VMs don't immediately use all their allocated disk space.

Directory storage is the simplest option, storing VM images as files on any mounted filesystem. Whilst it lacks advanced features, directory storage works reliably and integrates easily with existing storage.

Network Storage Options

NFS connects to network file shares, common with NAS devices. It's straightforward to configure and works well for shared storage in small to medium clusters.

iSCSI provides block-level network storage, typically from SANs. iSCSI delivers good performance and supports advanced features like multipathing for redundancy.

Ceph is distributed storage built into Proxmox, turning the local disks of multiple nodes into a unified, self-healing storage pool. Ceph provides excellent redundancy but requires at least three nodes and careful planning.

SMB/CIFS enables integration with Windows file shares, whilst GlusterFS offers another distributed filesystem option for those preferring it over Ceph.

Clustering and High Availability

Proxmox VE scales from single-node installations to multi-node clusters without requiring different licensing or additional products. Multiple Proxmox nodes form a cluster, enabling centralised management, resource pooling, and high availability features.

The Proxmox Cluster File System (pmxcfs) keeps configuration synchronised across all nodes using a distributed database built on Corosync. Changes made on any node propagate automatically to all cluster members, ensuring consistency.

High Availability Features

When configured for high availability, Proxmox monitors VM health and automatically restarts failed VMs on surviving nodes. The HA Manager responds to node failures within seconds, minimising downtime for critical services.

Live migration allows you to move running VMs between nodes without downtime, essential for performing hardware maintenance or balancing workload across cluster nodes. Shared storage (Ceph, NFS, iSCSI) is required for live migration, though offline migration works with local storage.

Clusters scale from small three-node setups to larger deployments. For organisations managing multiple clusters, Proxmox Datacenter Manager (PDM) provides centralised oversight and management across geographically distributed installations.

Backup and Disaster Recovery

Proxmox VE includes an integrated backup tool (vzdump) that creates consistent snapshots of VMs and containers. The snapshot process ensures backups capture a consistent state, even for running systems with active databases or applications.

Through the web interface, you can schedule automated backups with retention policies, choosing between full backups and space-efficient incremental backups. Backup jobs can run during off-peak hours to minimise impact on production workloads.

Proxmox Backup Server Integration

For more sophisticated backup requirements, Proxmox Backup Server provides dedicated backup infrastructure with enterprise features. Deduplication dramatically reduces storage requirements by eliminating duplicate data blocks across backups. Encryption protects backup data both in transit and at rest, critical for compliance requirements.

Incremental backups transfer only changed data, reducing backup windows and network bandwidth consumption. The innovative live-restore feature can start VMs directly from backup storage whilst data transfers in the background, minimising recovery time objectives.

What Makes Proxmox Different?

Understanding Proxmox's position relative to commercial alternatives helps frame its value proposition for infrastructure decisions.

Comparison with VMware

VMware vSphere has dominated enterprise virtualisation for years, but Proxmox offers compelling differences. There are no per-CPU or per-VM licensing costs with Proxmox - the software is free regardless of scale. All features are included in the base installation rather than being gated behind expensive tiers or add-on products.

Independent storage benchmarks from simplyblock found that Proxmox VE outperformed VMware ESXi in 56 of 57 storage tests, delivering IOPS performance gains of nearly 50%^[src]. Whilst these results are storage-specific and vendor-provided, they challenge assumptions about commercial software automatically delivering better performance.

Perhaps most significantly, the source code is available for inspection and modification. If you need custom functionality or want to understand exactly how your virtualisation platform works, that's possible with Proxmox in ways it simply isn't with closed-source alternatives.

Comparison with Microsoft Hyper-V

Hyper-V ties closely to the Windows ecosystem, making it a natural choice for Windows-centric environments. Proxmox isn't tied to any particular vendor's ecosystem, running on standard Linux and supporting diverse storage and networking options.

Container support differs significantly. Whilst Hyper-V has added some container capabilities, Proxmox's native LXC integration provides more flexible and efficient Linux container support. The web-based management interface also tends to be simpler and more intuitive than Hyper-V Manager or System Centre.

The Open-Source Advantage

Beyond feature comparisons, open-source software provides strategic benefits. There's no vendor lock-in - if Proxmox Server Solutions GmbH disappeared tomorrow, the software would continue working and the community could maintain it. Development happens transparently with public roadmaps and issue tracking.

Community contributions extend the platform through plugins, integrations, and shared knowledge. If you need to modify functionality or integrate with internal systems, you have the freedom to do so without violating licence agreements or waiting for vendor approval.

Licensing and Support Options

Proxmox's licensing model differs fundamentally from commercial virtualisation platforms, and understanding this distinction helps evaluate total cost of ownership.

The core software is completely free under the AGPL v3 licence. There are no feature restrictions in the free version - you get the full product including clustering, high availability, backups, and all management capabilities. The Community repository provides free package updates, though these receive less rigorous testing than the Enterprise repository.

Subscription Benefits

Proxmox Server Solutions GmbH offers optional subscriptions that provide access to the Enterprise repository with more thoroughly tested packages, professional technical support, and help sustaining ongoing development. Subscription tiers start with Community (EUR 115 per socket per year)^[src] and scale through Basic, Standard, and Premium levels with increasing support response times and coverage.

Critically, subscriptions don't unlock features - they provide support and access to a more stable update stream. You can run Proxmox in production without paying anything, though many organisations choose subscriptions for the peace of mind of vendor support.

Who Uses Proxmox?

Proxmox serves diverse users across a wide range of scales and sophistication levels.

Home Labs and Enthusiasts

Technology enthusiasts and students use Proxmox to learn virtualisation without licensing costs. You can experiment with clustering, high availability, storage replication, and other enterprise features in a home lab environment. This makes Proxmox popular in the self-hosted and homelab communities.

Small and Medium Businesses

SMBs appreciate Proxmox's cost-effectiveness - full enterprise features without enterprise pricing. Companies running 5-50 VMs find Proxmox delivers all the capabilities they need whilst keeping infrastructure costs manageable. The flexibility to mix VMs and containers lets businesses match each workload to the most efficient virtualisation approach.

Enterprises

Despite the "free software" label, Proxmox sees genuine enterprise production deployments worldwide. Organisations in IT services, software development, education, government, and other sectors run business-critical systems on Proxmox clusters.

Industry estimates suggest over 1.5 million hosts worldwide run Proxmox VE^[src], with the platform's community forums hosting over 200,000 active members. The Broadcom acquisition of VMware has accelerated Proxmox adoption as organisations reassess their virtualisation strategies in light of significant licensing cost increases.

What Proxmox Enables You To Do

Understanding capabilities helps frame whether Proxmox suits your infrastructure requirements.

Hardware consolidation reduces physical server count, cutting costs for equipment, power, cooling, and data centre space. We've helped clients reduce 30+ physical servers down to a handful of Proxmox nodes, dramatically simplifying their infrastructure.

Private cloud infrastructure gives you the flexibility of cloud computing without ongoing per-instance costs or data sovereignty concerns. For workloads that don't need to scale dynamically, private cloud often delivers better economics than public cloud.

Development and testing environments benefit from rapid VM/container provisioning. Developers can spin up isolated environments in minutes, experiment freely, and destroy them when done. This accelerates development cycles whilst maintaining production isolation.

Disaster recovery capabilities through VM replication and backup automation protect against data loss and extended downtime. Proxmox's backup tools integrate with your DR planning, and the ability to run VMs directly from backup storage minimises recovery time objectives.

Hybrid scenarios integrate with existing infrastructure. Proxmox doesn't demand all-or-nothing migration - you can deploy it alongside existing virtualisation platforms, gradually migrating workloads as appropriate.

Automation Ready

Proxmox provides a comprehensive RESTful API for programmatic control of all platform functions. This enables Infrastructure as Code workflows using tools like Terraform (via the Telmate provider) and Ansible for configuration management.

The API means you can automate everything from VM provisioning to backup scheduling to cluster configuration. For organisations with existing automation workflows, Proxmox integrates readily without requiring proprietary tools or languages.

Getting Started

Trying Proxmox requires modest hardware and minimal time investment.

Minimum Requirements

A 64-bit CPU with virtualisation support (Intel VT-x or AMD-V) is essential^[src] - most modern processors include this. Proxmox itself needs 2GB RAM minimum, though 8GB or more is recommended for production use. Plan 8GB storage for the Proxmox OS installation, preferably on an SSD for better performance. Any standard network interface works, though faster networking improves VM migration and storage replication performance.

Next Steps

Download the ISO installer from proxmox.com and either install on dedicated hardware or use nested virtualisation within an existing VM for evaluation. Once installed, access the web interface at https://[server-ip]:8006 and authenticate with the root credentials you set during installation.

The Proxmox documentation provides comprehensive guides for initial configuration, and the community forums offer help when you encounter questions. For production deployments, we recommend planning cluster architecture, storage design, and networking carefully before installation.

Conclusion

Proxmox Virtual Environment is a mature, enterprise-grade virtualisation platform that challenges assumptions about needing commercial software for serious infrastructure. Combining KVM and LXC virtualisation with integrated management, clustering, and backup capabilities, Proxmox delivers comprehensive functionality without licensing costs.

The open-source model provides transparency, flexibility, and freedom from vendor lock-in. Optional commercial support addresses enterprise risk management concerns whilst maintaining the core principle of freely available software.

Whether Proxmox suits your needs depends on your specific requirements, existing infrastructure, and team capabilities. For organisations seeking to reduce licensing costs, maintain control over their infrastructure, or build private cloud capabilities, Proxmox deserves serious evaluation.

This article has covered what Proxmox is and what it does. In Part 2 of this series, we'll explore why UK businesses specifically choose Proxmox, covering the business case, cost analysis against public cloud alternatives, and compliance considerations including GDPR and data sovereignty.

Next in Series

Part 2: Why UK Businesses Choose Proxmox - The Business Case for Private Cloud Infrastructure