VMware ESXi vs Proxmox VE: A Full Comparison

With the news of Broadcom acquiring VMware and the announced licensing and other changes, some organizations have started to look at VMware ESXi alternatives, such as XCP-ng, Nutanix AHV, and Proxmox VE. Considering the right hypervisor for your use cases allows virtualization to be used with maximum efficiency and to its full potential. Organizations must balance functionality, price, and usability when choosing a virtualization platform.

In this blog post, we compare ESXi and Proxmox in different categories, including features, performance, and licensing.

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Hypervisor Type

Both Proxmox and ESXi are type-1 hypervisors, also called bare-metal hypervisors. A type-1 hypervisor runs directly on the underlying hardware without the need to use an operating system as an underlying layer. As a result, maximum performance is achieved. Resources of this hardware are used for guest operating systems of virtual machines (VMs), which run logically isolated from each other.

What is Proxmox?

Proxmox Virtual Environment or Proxmox VE is an open-source hypervisor based on a Debian Linux distribution with a modified kernel to use KVM virtualization. The Proxmox Server Solutions company developed Proxmox VE in Austria. Proxmox VE was initially released in 2008.

What is ESXi?

VMware ESXi is a proprietary hypervisor developed by VMware. The main component in ESXi for running virtual machines is VMkernel. ESXi and VMkernel are not Linux, despite using many standard commands similar to Linux commands.

A server running ESXi is called an ESXi host, the main element of a VMware vSphere virtual environment. This allows you to use advanced virtualization features using multiple hosts. ESXi is a mature hypervisor, the first version released as far back as 2001.

Architecture

Proxmox and VMware virtualization solutions use different architectures.

Proxmox

The main component in Proxmox VE is the host on which Proxmox is installed. Multiple Proxmox hosts can be added to logical structures as a datacenter and connected as nodes in clusters. There is no need to install a special centralized tool for the management of the Proxmox environment, given the multi-master design.

VMware

VMware vSphere. VMware ESXi is the main component of VMware vSphere. VMware vSphere is the environment that contains multiple ESXi hosts that are managed centrally.

vCenter Server is a solution for centralized management of VMware ESXi hosts using advanced features such as VM migration, clustering, vSAN, Kubernetes, distributed virtual switches, etc. Add-ons are installed using vCenter in vSphere.

Storage

Proxmox vs VMware vSphere storage options have significant differences.

Proxmox

File systems

Proxmox uses the clustering file system called pmxcfs, which is database-driven and is used to distribute a cluster configuration to all nodes transparently. Proxmox configuration files are stored in this file system.

Supported file systems for VM datastores are ZFS, BTRFS, pmxcfs. LVM volumes are supported.

Shared storage

NFS and iSCSI shared storage can be connected to Proxmox hosts using Debian Linux tools.

Thin provisioning

Thin provisioning is supported for ZFS and Ceph file systems and LVM-Thin volumes on datastores. It must be enabled at the datastore level and for VM disks. You may need to run special commands like fstrim -av to free up datastore space after deleting data inside virtual disks (free space reclamation). Additionally, you may need to enable the fstrim.timer service on virtual machines. The qcow2 image format for VM disks must be used to support thin provisioning.

Virtual disk format

Proxmox supports .vmdk, .qcow2 and .raw virtual disk formats. You can import .vmdk virtual disks from VMware VMs to Proxmox with a few commands. The native format is .qcow2 for Proxmox.

Snapshots

The virtual disks of a VM must use the QEMU copy-on-write (qcow2) format to use VM snapshots in Proxmox. Live snapshots of running VMs are supported in this case to save the virtual machine state. The snapshot number limit is not specified.

VMware

File systems

VMware ESXi uses a VMware clustering file system called VMFS. Special lock mechanisms are used to allow multiple hosts to work with the same files on shared storage used by hosts in a cluster. VMFS is also used on local datastores and is optimized for virtualization and thin provisioning. The latest versions of ESXi and VMFS support automatic free space reclamation (UNMAP) after VM data is deleted from VMDK virtual disks.

VMware vSAN is a hyper-converged solution that allows you to configure a vSAN cluster using directly attached storage on multiple ESXi hosts as a single storage pool available from all cluster nodes to store VMs.

Shared storage

VMware ESXi hosts support NFS and iSCSI shared storage.

Virtual disk format

VMDK is the native VMware format and the only virtual disk format for VMware ESXi hosts. The raw data of a virtual disk is stored in a -flat.vmdk file, and the virtual disk descriptor that explains the virtual disk parameters and structure is stored as a .vmdk file.

Snapshots

VMware ESXi supports live snapshots of running virtual machines and stopped virtual machines. The maximum number of snapshots in a chain for a VM is 32.

Thoughts

Proxmox supports more virtual disk formats and file systems for datastores, but VMware ESXi provides more convenient options for thin provisioning.

The table displays a summary of the main Proxmox vs ESXi storage parameters:

Networking

Proxmox

Proxmox uses the Linux network stack, which adds more flexibility to network configuration. Linux tools are respected for their broad and advanced networking capabilities. It also means that Proxmox administrators should know network principles. A basic network configuration can be done in the GUI, but the command line is used for advanced configuration and fine-tuning.

You can use the following networking setup and configuration models on a Proxmox server for VMs:

• Bridge, routed, port forwarding, masquerading (NAT) with IP tables.
• VLAN 802.1Q and link aggregation (NIC teaming) are supported. Link aggregation is configured in Linux configuration files.

Proxmox supports Open-vSwitch, which can be used as an alternative to ESXi virtual switch.

VMware ESXi and vSphere

VMware ESXi uses bridged networking mode with a standard virtual switch by default. This virtual switch supports VLAN configuration. Standard virtual switches can be configured in VMware Host Client. To avoid configuring standard virtual switches on each ESXi host in vSphere with the same configurations, you can configure a distributed virtual switch in vCenter using VMware vSphere Client. A distributed virtual switch is available only for the top vSphere edition.

Configuration of link aggregation is user-friendly and can be done in the GUI of VMware Host Client or vSphere Client.

NSX is a software-defined networking solution that can be installed as an add-on for vCenter as VMs on ESXi hosts. VMware NSX allows you to implement a complex network configuration for large datacenters. NSX requires advanced skills to set up.

Thoughts

Proxmox supports a broad set of advanced and flexible network features out of the box, but configuring them requires expertise and a good understanding of network principles. The basic networking configuration in ESXi is straightforward. A distributed virtual switch is a great and unique VMware feature for large virtual environments. For more complex network configurations in large datacenters, you can deploy the VMware NSX solution.

VM Live Migration

Both Proxmox and VMware vSphere support VM live migration from one host to another without downtime (the downtime can be a few milliseconds). Processors of the same family must be used for this purpose. The latest versions of Proxmox (as other KVM implementations) and vSphere support VM live migration even without shared storage, but this would take more time.

Proxmox VE

VM migration works inside a cluster. Additionally, there is a new feature for migrating VMs between clusters. Note that a standalone Proxmox server can be a one-node cluster. To migrate VMs between clusters, you need to use the command line and create API tokens on clusters.

VMware vSphere

VM Live migration is performed with the vMotion feature. Storage vMotion is responsible for migrating VM files, while vMotion moves CPU and memory workloads from one host to another. To migrate VMs between ESXi hosts in vSphere, creating a cluster is not necessary. VMs can be migrated even if they are not in a cluster. VM migration can be initiated in the GUI of VMware vSphere Client in vCenter or in PowerCLI.

Thoughts

VMware provides more convenient tools and flexible options for VM migration and VM live migration. Proxmox supports live migration, but creating clusters and using the command line can be less convenient for some users.

Clustering

Clustering is a key feature of an enterprise-grade virtualization solution. In this section, Proxmox alternatives to VMware clustering are overviewed.

Proxmox

Proxmox allows you to easily create a cluster of servers to manage VMs and containers centrally. It uses Corosync Cluster Engine for cluster communication, which provides a reliable and scalable clustering service, alongside QDevice for enhanced quorum in split-brain scenarios. The pvecm is the tool called Proxmox cluster manager that can group hosts into a cluster. However, cluster management is performed in the same Proxmox web interface, as usual. The Proxmox VE cluster enables shared storage, migration of VMs, and high availability without additional cost.

High availability. Proxmox offers a high-availability solution that ensures VMs and containers automatically restart on another node if the current node fails. The configuration may require a bit more manual work compared to VMware but is fully featured within its GUI and accessible without additional licensing fees.

Load balancing. Proxmox implements simple built-in load balancing through its REST API or GUI, which can be used for manual or automated migrations of VMs and containers based on resource usage. While this type of balancing doesn’t feature an automatic dynamic resource scheduler like VMware, it offers enough for basic load balancing and resource allocations.

VMware vSphere

VMware provides advanced clustering features for any scenario. Clusters are managed in vCenter by using vSphere Client or PowerCLI. Organizations should buy higher-level licensing editions to unlock the clustering features.

High availability. HA uses fast, reliable, and efficient mechanisms for failure detection, migration, and recovery (failover) of VMs in a cluster. The smartest feature of a VMware HA cluster is Fault Tolerance. VM failover with High Availability enabled requires a little downtime after VM failure and before the restart of the VM migrated to another ESXi host. A VM with enabled Fault Tolerance in an HA cluster is failed over immediately and seamlessly. This happens because a transparent VM clone (ghost VM) is continuously running on another ESXi host with a replicated state of the original VM but with disabled input-output interfaces.

Load balancing. Distributed Resource Scheduler (DRS) is a sophisticated feature that automatically balances computing workloads with available resources. It continually monitors utilization across resource pools and intelligently allocates available resources among VMs. DRS can dynamically (and automatically) respond to changes, enhancing performance and eliminating resource bottlenecks, but it requires higher-level editions of vSphere. There is also a Storage DRS feature to balance storage use and storage load.

Thoughts

VMware provides more advanced clustering features compared to Proxmox, but requires a larger budget to buy licenses. Proxmox, in turn, has a set of clustering features that are affordable for everyone. VMware vSphere can be suitable for large enterprise organizations, while Proxmox can be a rational choice for small and medium organizations from a clustering perspective.

Device Passthrough

Device passthrough is a powerful feature in virtualization environments that allows virtual machines (VMs) to access and utilize hardware components directly, bypassing the hypervisor. Both Proxmox and VMware ESXi (vSphere) support device passthrough, but they handle it differently.

Proxmox

Proxmox VE supports device passthrough using a combination of technologies, including IOMMU (Input-Output Memory Management Unit) groups for hardware that supports this feature, such as Intel VT-d and AMD-V.

PCI passthrough allows VMs to use physical PCI (PCIe) devices installed in a Proxmox server directly without being virtualized. These devices can be graphic cards, network cards, etc. Most configurations are made in the command line.

USB passthrough. USB 3.0 and USB 2.0 devices are supported. USB configuration can be done in the web GUI, but you can also use all configuration options in the command line. USB drivers must be installed in a Guest OS of a VM to use this feature.

VMware ESXi

VMware ESXi takes a slightly different approach towards device passthrough, often referred to as “DirectPath I/O” and also supports a wide range of devices.

PCI passthrough. ESXi uses Dynamic DirectPath I/O to connect physical PCI(e) devices to VMs. ESXi 7 and later also support NVIDIA GRID technology to share GPU resources of a physical video card with VMs on an ESXi host.

USB passthrough. The USB arbitrator on an ESXi host is responsible for USB passthrough and defines whether a USB device is connected to a host or VM guest. Configuration can be done in multiple ways, including the GUI, and is user-friendly.

Thoughts

Proxmox utilizes open-source technologies and might require a bit more hands-on configuration, offering a high level of flexibility. VMware ESXi’s DirectPath I/O feature, while a bit more restrictive in terms of VM features, offers a streamlined and integrated setup process through vSphere Client.

Containers

Containers are another form of virtualization, a lightweight alternative to virtual machines. Unlike VMs using a guest OS and underlying provisioned hardware, containers share a kernel of a host operating system to run applications in logically isolated environments.

Proxmox VE

Proxmox uses Linux OpenVZ to run containers and supports Linux containers (LXC) as the container technology.

Proxmox supports only Linux distributions to run containers. Windows and FreeBSD are not supported.

Containers are integrated with Proxmox VE – they use networks and clusters available for VMs.

VMware vSphere

VMware uses Tanzu as a container orchestration platform that supports Kubernetes to run containers in VMware vSphere. The ideology of running containers in VMware Tanzu differs from the Proxmox approach. You need to deploy control plane VMs and a load balancer. Additionally, you need to deploy working nodes as VMs to run containers in Kubernetes.

VMware NSX should be used to configure networking for containers. It is also possible to use ESXi hosts as vSphere pods for containers. VMware Tanzu is a massive solution that must be deployed additionally in vSphere, compared to out-of-the-box support of Linux containers in Proxmox.

Guest Agent Tools

VMware provides VMware Tools, which is a set of drivers and utilities to install on guest operating systems for better performance and user experience.

Proxmox provides QEMU Guest Agent to be installed on guest OSs of VMs for the same purpose.

Installing VMware Tools and QEMU Guest Agent on Linux guests is identical and is performed using a package manager, such as apt-get for Debian and Ubuntu, from online software repositories.

As for installing on Windows guests, QEMU Guest Agent is included in a package of VirtIO drivers. VMware provides a user-friendly installer for Windows. Windows installers for Windows guests for both solutions are released as ISO images that should be mounted to VMs.

Performance

As both Proxmox and VMware ESXi are type-1 hypervisors, they provide high performance. Both solutions meet high industry standards in terms of performance for enterprise organizations. While the maximum supported configuration of ESXi hosts in vSphere is limited by a license, you can add an unlimited number of Proxmox hosts to achieve the needed performance.

You can get an accurate comparison of Proxmox vs ESXi performance only if you configure Proxmox and VMware ESXi/vSphere environments on the same hardware and perform tests with measurements. Nevertheless, there are factors that cannot be equalized, such as maximum configuration limits, compatibility, ease of deployment and configuration, usability, the way to upgrade, etc. These factors have an indirect impact on performance.

Max limits

As for defined limits, Proxmox supports the following maximum limits (note that some limits are higher than supported by existing hardware: 8096 logical processor cores per host.

The comparable limits of Proxmox and VMware ESXi are listed in the table.

Compatibility and Integration

Proxmox

The advantage of Proxmox is that this solution, as a Linux-based solution, can be installed on most hardware, even on older hardware. Both solutions require processors with hardware virtualization features, such as Intel VT-x or AMV-V. Proxmox is price-friendly from a compatibility perspective.

VMware vSphere

VMware ESXi can be installed only on supported server-grade hardware, and you should read the hardware compatibility list carefully. When new vSphere versions are released, the support of older hardware is removed from the ESXi distributions. As a result, when upgrading the ESXi version, you may need to buy new servers for compatibility reasons. This, in turn, results in investing more in costs.

Thoughts

Proxmox can be considered a more hardware-friendly solution for any environment.

Deployment

Both Proxmox and VMware vSphere solutions are deployed in different ways, using different workflows.

Proxmox

The Proxmox deployment starts with downloading the ISO image, which includes a complete Debian Linux operating system with virtualization software and optimizations to run VMs and containers. After booting from the installation media, for example, from a USB flash drive to which a bootable ISO image was written, you need to follow the installation wizard in the graphical user interface. This approach simplifies the installation process. After finishing the installation, the link to access the Proxmox web interface is displayed.

VMware vSphere

ESXi deployment is straightforward: You need to boot from the installation medium (distributed as an ISO image) and follow the few steps of the ESXi installation wizard in the pseudo graphical user interface.

VMware vCenter deployment is slightly more complicated than ESXi. You need to enter all parameters attentively and ensure that DNS names are configured and resolved correctly. However, the newest vCenter Server deployment method using vCenter Server Appliance (VCSA), which is a preconfigured VM based on Linux Photon, is user-friendly. VCSA is a preconfigured VM template aimed to make deployment easier.

Ease of Use and User Interface

Proxmox

Proxmox provides a user-friendly web interface to manage Proxmox hosts and virtual machines residing on the hosts. This graphical user interface is available in a web browser after installing Proxmox, and there is no need to install a separate tool manually.

Users can connect to any node of a Proxmox cluster to manage the entire cluster. There is no need to install a special cluster management tool (such as Hyper-V Failover cluster Manager). The AJAX technologies are used to display an updated environment in the web interface as soon as possible.

The command line tools in Proxmox are excellent. Some actions cannot be performed in the graphical user interface of Proxmox. In this case, the command line must be used. You can access the Proxmox command line from the web interface by going to Datacenter > nodename > >_ Shell to manage the needed item.

VMware

VMware Host Client is an embedded web interface that is available on each ESXi host after ESXi installation. This graphical user interface is user-friendly and allows you to configure the host and VMs. You can manage VMs and open a VM web console to manage a guest operating system (OS), similar to when you connect a monitor to a machine.

Direct Console user interface (DCUI) is a basic pseudo-graphical user interface (presented in yellow and grey colors in DOS style) that allows you to make a basic configuration of ESXi, such as setting network interfaces, a hostname, SSH access, etc.

ESXi command line is a user interface where you can make advanced configuration of an ESXi host. ESXi command line unlocks configuration capabilities that are not available in DCUI and VMware Host Client. You can connect to the ESXi command line directly on an ESXi server using ESXi Shell or remotely via SSH using an SSH client.

VMware vSphere Client is a web interface provided by vCenter Server for centralized management of vCenter, ESXi hosts, clusters, add-ons, and other components of VMware vSphere. VMware vSphere Client is a powerful and convenient graphical user interface.

VMware Remote Console (VMRC) is a special application installed on Windows that can be used for connecting to VMs instead of a web-based VM console. VMRC is more convenient with the added advantage of better image quality when opening the user interface of the guest OS.

VMware vSphere PowerCLI is another type of command line interface for managing standalone ESXi hosts and vCenter servers. PowerCLI is a set of special PowerShell cmdlets created by VMware. This command line interface can be convenient for those who like PowerShell to automate tasks.

Update and Upgrade

As for the Proxmox vs VMware vSphere comparison in terms of update, both solutions are updated in different ways, especially when it takes to mass update or upgrade.

Proxmox

To update Proxmox, you should use the command line of Linux Debian, where Proxmox is running. See the official Proxmox documentation about the commands and scripts that you should use for the needed version. Additionally, you can access the Proxmox update options in the Proxmox web interface. The difficulty of updating and upgrading can be classified as medium.

You can use scripts and an SSH connection to update multiple Proxmox hosts in an automated batch manner.

VMware vSphere

To update VMware ESXi, you need to use the ESXi command line interface to update a single host or vCenter Server to update any number of hosts centrally. Download the new version of an ESXi image to update and run the appropriate commands to update/upgrade ESXi. Mass updating of ESXi hosts in vCenter can be done using VMware Lifecycle Manager images. The difficulty of the update process can be classified as medium but with optimization for updating multiple hosts.

You should stop VMs or migrate VMs to other hosts before starting the update process (for ESXi and Proxmox).

Integration APIs and Backup

The API capabilities are also a significant consideration when choosing a virtualization solution because effective VM protection is crucial for organizations.

VMware vSphere

VMware offers extensive APIs and SDKs for interacting with vSphere, including functionalities for data protection:

• vSphere API provides access to VMware vSphere management components. There’s a comprehensive set of operations for VM management, including backup and restore capabilities, array integration, etc.
• vSphere Storage APIs – Data Protection (VADP) is specifically designed for backup and restore operations. It allows third-party software to efficiently perform host-level backup and restore for VMs without heavily impacting system performance.

These APIs are well-documented and supported, with extensive resources, community forums, and VMware’s own support services. Developers can use these APIs to build custom backup solutions that can interact deeply with the vSphere ecosystem.

Proxmox

Proxmox VE REST API is a comprehensive API that provides access to all Proxmox VE resources and settings, including VMs, storage, and network configurations. The REST API is used to manage Proxmox VE programmatically and can be accessed using standard HTTP methods.

Regarding data protection, while Proxmox VE includes built-in backup and replication features, its approach and the API support for these features might not be as direct or specialized as VMware VADP. Proxmox’s backup solutions (like vzdump for container and VM backups) can be automated or managed through the REST API, but the system might not offer an exact analog to VMware VADP specifically dedicated to data protection.

However, it is entirely possible to develop host-level backup solutions for Proxmox VMs using the Proxmox VE REST API. The API allows for managing VM snapshots, backup jobs, and storage, which are essential components for creating a backup solution. Developers can automate backup tasks, manage backup storage, and even integrate solutions with third-party storage or backup solutions through custom scripts or applications.

Security

Proxmox and VMware vSphere provide a security level that is enough for enterprise organizations and production environments.

Proxmox VE

The Proxmox VE security features:

• The GUI uses HTTPS with SSL encryption.
• Role-based access control (RBAC) and permissions, integration with Linux PAM.
• Centralized authentication via LDAP and Active Directory.
• Supports two-factor authentication.
• Proxmox has an integrated firewall that can control traffic from/to a cluster node or specific VM.
• Proxmox VE Offers ZFS for encryption at the file system level for storage, adding an additional layer of data protection. VM disk encryption isn’t built directly into Proxmox, but since it supports running VMs on LUKS-encrypted volumes, disk encryption can be achieved.
• Regular updates are provided, and the community-driven approach ensures rapid response to vulnerabilities. However, it is the responsibility of the administrators to apply these patches in a timely manner.

VMware ESXi and vSphere

Security features of VMware vSphere are:

• Role-based access control is more granular.
• Two-factor authentication and Smart Card (Common Access Card) authentication.
• Encryption when accessing the graphical and command line user interfaces.
• Comprehensive encryption capabilities, including VM encryption, vMotion encryption, and encryption for data at rest and in motion. These encryption features use AES-256 algorithms and are managed through the vCenter Server.
• VMware has a structured approach to security patches and updates, issuing regular advisories and updates. Patch management can be more streamlined through Update Manager in vSphere environments.

Thoughts

VMware ESXi/vSphere generally offers a broader and more integrated set of advanced security features, attributable to its widespread adoption in enterprise environments where security demands are strict. While offering a robust set of security tools, Proxmox VE offers more flexibility and integration with open-source technologies.

Pricing and Editions

The pricing approach of these two virtualization solutions is completely different. Some organizations consider Proxmox as a VMware ESXi alternative but is available for free (without any charge). Free ESXi is not available anymore.

Proxmox

Proxmox is an open-source solution available under the GNU General Public License, which means that this hypervisor is available for free and without limitations. However, you can buy an enterprise subscription to extend support and updates that can be important for mission-critical production environments. Enterprise packages pass more detailed debugging and testing stages. You can mix free and subscription-activated servers in a single environment.

The Proxmox subscription is available in different plans:

• Community: €110/year and CPU socket.
• Basic: €340/year and CPU socket. 3 support tickets yearly.
• Standard: €510/year and CPU socket. 10 support tickets per year.
• Premium: €1020/year and CPU socket. An unlimited number of support tickets.

VMware ESXi/vSphere

VMware ESXi and its virtualization solution vSphere require buying a VMware vSphere license to use ESXi and a vCenter license to use vCenter Server for centralized management of multiple hosts and using additional features. Additional components you install in VMware vSphere as add-ons, such as vSAN, NSX, Tanzu, must also be licensed with a paid license. Technical support is included. VMware vSphere products are available in multiple editions. Contact VMware to know the latest price, as the price is not displayed on the website.

VMware discontinued ESXi Free Edition (which was licensed as a VMware vSphere Hypervisor for free). Now, there are no free ways to use VMware ESXi after Broadcom acquired VMware. This acquisition also led to the deprecation of perpetual licenses. Now you can buy a subscription to license VMware vSphere components on a per CPU socket or workload basis.

Trial

VMware allows you to use a free full-featured trial mode for 60 days for ESXi, vCenter, and other vSphere components. Then, you must install a license.

In contrast, as Proxmox is free, the trial period is not relevant for Proxmox.

Thoughts

Proxmox offers more attractive options in terms of pricing and licensing. It can be a key point for organizations that cannot afford to pay for vSphere licenses when choosing a backup solution.

Summary Table

The main points of the Proxmox vs VMware comparison are summarized in the table below.

*macOS is supported on ESXi if supported hardware is used with a patch installed on ESXi.

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