KVM vs OpenVZ – Which is better?

Short Answer (quick read).

The question “KVM vs OpenVZ” can be answered by taking a quick look at both systems. So, here we go:

The differences between KVM and OpenVZ are:

OpenVZ (Open Virtuozzo) is easier to configure and easier to maintain than KVM VPS. However, this system can be slower than KVM under specific circumstances and it is limited to Linux Operating Systems only. OpenVZ can be managed by the provider, usually at additional charges.

KVM (Kernel Based Virtual Machine) can host any operating system. This system is always self-managed which means that the customer is the one to manage this software.

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Hopefully this summary was good enough to explain which of the two is better, KVM or OpenVZ. However, we invite you to read on to learn everything about the details.

Long explanation.

A comparison between OpenVZ and KVM.

What is a KVM Server?

It’s a virtualization solution that uses the infrastructure of the Linux kernel for complete virtualization. With such a kernel-based virtual machine, the complete virtualization of any operating system is possible. In contrast to OpenVZ the entire operating system is virtualized, including its own kernel and individual network settings. Even the installation of non-Linux systems is possible without any problems. At first, KVM only seemed to represent a niche solution, but with version 2.6.20, following direct implementation in the Linux kernel, it rose to become the de facto standard for full virtualization in the Linux area. The leading distributors Suse Linux, Red Hat, CentOS and Ubuntu have been using this system as the preferred virtualization solution over its predecessor XEN for some time now.

How much does a KVM Server cost?

The prices for these servers are based on the traffic, RAM and possible storage space provided. Very affordable offers with a few gigabytes of storage space and less than one gigabyte of RAM are available at low monthly prices. Significantly more powerful servers are available at higher prices, whereby the upper limits are open. Here it is important to check your own needs carefully. Setting up a KVM Server is usually free of charge, some providers charge low fees. In the case of very cheap offers, the selection of the available operating systems can sometimes be limited.

Who offers KVM Servers?

Most known providers of network services now offer this service. In addition to premium providers, it is often worth taking a look at smaller providers who have affordable entry-level offers. When choosing a provider, your own needs and the reliability of the respective provider, together with the price, should play a decisive role.

What are the advantages and disadvantages of KVM?

Compared to OpenVZ, KVM offers some advantages that result from full virtualization:

  • Installation of own images possible
  • Installation and configuration of your own kernel
  • Firewall over iptables
  • Snapshots can be created during operation
  • The size of the SWAP memory can be freely determined
  • Top security and speed.

Disadvantage: It’s more difficult to set up and manage than OpenVZ.

What alternatives to KVM are there?

In the case of virtualization via a kernel-based virtual machine, in principle all type 2 hypervisors can be considered. These are based on a normal operating system and use its drivers. Well-known alternatives are for example Microsoft Virtual Server, OpenVZ or Linux Server.

What is OpenVZ and how does it work?

It’s software developed from the commercial Virtuozzo project for the virtualization of operating systems. It uses a specially adapted Linux kernel that administrates the distribution of resources between the running subsystems. In contrast to commercial solutions like VMWare, it uses the open source license GPL V2. All operating systems run at OpenVZ in individual, strictly isolated containers. Each container is assigned a fixed storage capacity as a virtual hard disk. The additional environment, such as the available RAM memory or the proportion of CPU usage, can also be defined individually for each container. One of the special advantages of this technology is that the assignment can be changed at any time. It is not necessary to shut down the running system. Access from one container to another is not possible within the software. The system therefore offers a high level of security. From the user’s point of view, an OpenVZ server differs from a physical server in only a few details. One restriction is that you cannot install your own kernels.

What are the costs of an OpenVZ server?

The real costs depend heavily on the provider. They are calculated according to the size of the permanently allocated and variable RAM memory, the capacity of the hard drive and, under certain circumstances, the network traffic. Since it’s open source, unlike commercial solutions, there are no license fees for the provider. These servers are therefore usually cheaper than other virtual servers with comparable equipment. Some providers charge additional setup costs when installing the system. An upgrade to higher capacities, for example for more computing performance or a larger storage space, is usually possible without any problems and at no additional cost.

Which web hosting companies offer OpenVZ servers?

It is not always clear to the customer which virtualization solution a provider is using for its systems. In most cases, however, it does not play a decisive role, as it provides a complete operating system regardless of the software used. Many web hosts use OpenVZ in parallel to other programs such as Xen or VMWare. If the customer expressly wishes to operate this, he can fall back on the correspondingly marked offers. Otherwise, a simple short query to the provider clarifies whether they offer the technology or only use other virtualizations. However, OpenVZ holds a relatively high market share because of its efficiency, stability, and security. Many virtual Linux servers are therefore controlled via this method.

What are the advantages and disadvantages of OpenVZ?


  • Low costs thanks to open source software
  • Server properties can be changed during operation
  • Different Linux distributions are possible
  • Full operating system with root access
  • Unlimited software installation possible
  • Safe environment through isolated containers
  • Relatively easy to set up and handle


  • All containers use the same kernel
  • OpenVZ only supports Linux servers
  • Kernel cannot be updated or modified
  • Graphic systems are not always supported

What alternatives to OpenVZ are there?

Because of its simple configuration, its high performance and other advantages, OpenVZ has a high market share in virtual Linux servers. In recent years, many larger providers have increasingly been using KVM VPS to counter problems such as the lack of support for their own kernel.

Difference between KVM and OpenVZ.

OpenVZ solution

It’s not real virtualization. The VPS uses parts of the Linux OS but creates separate environments as VPS for the individual users.

This also includes a restriction: you access the hardware directly – without virtualization. So all users are sharing the RAM. So, for example, 40 hosts with 1 GB Ram can be operated on a server with 30 GB. As long as not all the Memory is used, it’s okay – but if all users want to use the Memory made available, simultaneously, it will have a significant impact on performance. The system will be slower.

KVM solution, for even more performance.

Normal servers are provided with Linux Servers (container virtualization). KVM, on the other hand, is 100% virtualization. So it gives you access to all functions that are related to the hardware. This will give you the absolute maximum power over your VPS. Non Linux operating systems can easily be installed. Now it looks much more like you have your own dedicated web server. The technology offers the possibility of importing and configuring your own kernels. The booked hardware resources are now fully assigned to the virtual instance, which guarantees a very stable operation.


To conclude this article we can say in general that more advanced users will probably opt for the KVM solution while, in most cases, less experienced users will prefer to use the OpenVZ system. As you have been able to read both systems are based on excellent virtualization techniques and both are probably equally popular among VPS users. Good luck with your VPS! We hope that your question “OpenVZ or KVM” has been answered and that it makes the choice easier to you.