OpenVZ vs KVM

Posted by / Mar 15, 2016 / Categories: Getting Started

BHost currently offers two virtualization technologies for your virtual machines – OpenVZ and KVM. For many users it makes little difference which technology you use. However, there are differences between the two systems which are explained here.

OpenVZ

OpenVZ is is a linux based virtualization platform based on the Linux Kernel. OpenVZ allows a physical server to run multiple isolated operating system instances known as containers. OpenVZ can only run linux based operating systems such as CentOS, Fedora, Ubuntu or Debian.

KVM

KVM is a hardware virtualization technology. This means the main OS on the server simulates hardware for another OS to run on top of it. It also acts as a hypervisor, managing and fairly distributing the shared resources like disk and network IO and CPU time.

Differences

Upgrades

With OpenVZ, you can change your plan (e.g. to get more memory or disk space) and you’ll instantly have your new system resources. On KVM, you’ll need to reboot your virtual machine for the change to take effect.

Operating Systems

OpenVZ only supports Linux. KVM can operate Linux as well as other operating systems such as Windows or BSD. We are primarily a Linux VPS provider but we do allow installation of FreeBSD and offer Windows machines on request.

Kernel

KVM requires a running kernel inside the VPS, whereas OpenVZ runs many containers using a shared kernel. Therefore, if you need control of your own kernel you should opt for KVM. For example, you might need to modify or patch the kernel. On the other hand OpenVZ has a shared kernel used by all containers. Having a shared kernel gives a slight performance advantage as there is no overhead from running a kernel within a kernel.

Management

OpenVZ is simpler, and is easier to manage as a result. KVM has many more options and settings which can cause complication.

About the author
I'm George and I work in the BHost support team. I'm responsible for replying to customer support requests, as well as writing articles for our help center. If there's anything you'd like us to blog about, let us know by emailing support@BHost.net