December 17, 2020

KVM vs VMware: 2021 Review

Written by

When looking to implement virtual machine (VM) hypervisors, most companies will compare KVM vs. VMware hypervisors.

Choosing between KVM and VMware hypervisors will require understanding your hardware, IT resources, and performance needs, along with a good understanding of your company’s financial needs. This article weighs those options.

What is the KVM hypervisor?

Kernel-based virtual machine (KVM) is a Type 2 Linux hypervisor that acts as a Type 1 hypervisor, as it runs on hardware that has virtualization extensions for Intel VT or AMD-V processors. KVM is made up of a loadable kernel module (kvm.ko) and a processor-specific module for Intel or AMD used to host Linux and Windows images on virtual machines with the QEMU userspace. KVM is available as a free open source software download, but there are commercial support options from vendors like Red Hat or Oracle.

What is the VMware ESXi hypervisor?

The VMware hypervisor ESXi is a bare metal type 1 hypervisor designed to run on a physical server to partition hardware. The previous version, ESX, loaded a Linux kernel as a service console, but the Linux kernel was dropped in version 4.1. ESXi now uses the vmkernel to run hardware, the guest computing systems, and the service console. ESXi also requires either the free vSphere software or a paid subscription vSphere 7 plan.

Also Read: VMware vs. VirtualBox for Desktop Virtualization

Pricing for KVM vs. VMware

These tools both come in free or paid options. KVM is available as a free and open source tool with optional support options. VMWare’s ESXi hypervisor and vSphere virtualization software are available with limited capabilities at a free tier with extended features and support available at paid levels.

Hardware requirements

KVM can be installed on a range of servers as long as they have the Intel VT or AMD-V processors. This gives you more flexibility when choosing hardware vendors and for future iterations of your server architecture.

VMware claims a piece of hardware when you install ESXi. This means that upgrading to new versions of ESXi or vSphere may render your older hardware obsolete.

Performance

The Linux kernel gives KVM a single level of abstraction but doesn’t affect performance. VMware tends to play up that ESXi is a true bare metal hypervisor, and therefore has faster processing, but the difference is negligible to most users.

The difference between KVM vs. VMware performance really has to do with the tools that run the virtualization capabilities. That said, VMware’s vSphere 7 released Monster VMs, which double the performance and capacity for clusters.

Support

KVM support is provided through several well-respected vendors like Red Hat or Oracle, and there is a vibrant community of home lab and professional server admins available for help. As with any open source tool, you’ll want to ensure that you have enough in-house or outsourced resources to set up, run, and maintain the software.

VMware is designed with enterprise corporations in mind, and the support options reflect that vertical’s need. VMware support ranges from 24/7 developer support to on-premises support staff, and everything in between. Verified resellers, contractors, and industry-specific support options are available.

Which is best for small, medium, and large enterprises?

As an open source software, KVM’s total cost of ownership (TCO) will win for small businesses nearly every time. While VMware offers a free version of ESXi and vSphere, companies that look to scale their VM efforts will quickly need to increase their plans, which may mean they switch to another option quickly.

Medium to large enterprises may want to consider VMware over KVM for its scalability and support. As these companies grow in scope and complexity, the support and technical capabilities of VMware will only serve them better.

Overall, companies who have more employee resources than cash on hand should consider KVM, while those looking to scale quickly will want to consider VMware.