What is the Difference Between OpenVZ and KVM?

What is the Difference Between OpenVZ and KVM?

VPS Hosting has brought in a revolution in its own terms, with its stability and reliability. The idea of having a complete server dedicated to your business without having to lease out the whole physical server has significantly upped the hosting game. If you have already decided on the VPS Server Hosting, choosing from a number of platforms and options under it may be confusing at times. You may have come across names likes OpenVZ, Virtuozzo, Cloud VPS and KVM VPS. Out of the many alternatives available in the market, the OpenVZ and the KVM options are the major ones.

Major differences between OpenVZ and KVM

While OpenVZ is a Linux based virtualization platform based on the Linux Kernel, the Kernel-based Virtual Machine (KVM) platform offers full virtualization with the unique kernel module. KVM basically turns a Linux into a hypervisor which can host multiple VMs. Since it uses a guest OS in each of the virtual machines, it can run multiple OSes such as Solaris, Linux, Windows, macOS and BSD. On the other hand, the OpenVZ platform can only run on the Linux OS.

OpenVZ allows only OS-level virtualization and does not allow its users to modify the kernels. The kernel is shared by all users on the same node, and upon reaching the allocated RAM for a user, the remaining ones become free for all users. This may not be a problem for running a small application but could be a roadblock for a more resource-intensive application. As for the KVM, it provides kernel-level virtualization with each virtual level having its own RAM, kernel, a network card, graphics adapter etc. It allows the user to set a minimum and maximum values to the resources to optimize resource allocation, thereby using more resources than OpenVZ, from a host’s perspective.

OpenVZ often comes with predetermined templates which can be easily installed even by someone not having much of the technical knowhow. It is less complicated to maintain compared to a KVM platform which requires little knowledge of networking.

In an OpenVZ, you are at your host’s mercy for the kernel modules, and it’s up to them to add any additional features. A failure in one shared kernel can end up affecting all the VPS instances on that server. KVM offers more flexibility with the option to customize the kernels. You can easily upgrade your OS without reinstalling the template.

Which one to choose?

These small differences can make a huge impact on your experience with virtualization, and when it comes to selecting one between them, it comes down to individual situation and context. OpenVZ, with its simplicity and cost-effectiveness, attracts more of the new entrants of VPS Hosting. However, if your need is a dedicated server for bigger businesses or gaming purposes, then KVM is a clear winner. Even if you are going for OpenVZ, make sure to avoid host providers involved in overselling. Overselling means a provider divides a server into many containers to oversell. KVM, although pricey, provides more reliability and stability and is better suited for serious players.