KVM or OpenVZ which virtualization is absolutely better?
KVM or OpenVZ ? Which virtualization is better for internet servers ? This question comes up often when a customer is searching for buy a Virtual Private Server. What a client should do first is to consider the amount of RAM and disk space he/she needs, then look into which virtualization technology web hosting company offers. There are many technologies in the market like Hyper-V, Xen, VMware, let’s speak about more frequent types: KVM and OpenVZ.
Table of Contents
Overview of KVM and OpenVZ
KVM (Kernel-based Virtual Machine):
– KVM is a full virtualization solution integrated into the Linux kernel. It allows users to run multiple isolated virtual environments, known as virtual machines (VMs), on a single physical server.
– Each VM operates with its own kernel and is fully capable of running any operating system, including various distributions of Linux, Windows, and others.
– KVM leverages hardware virtualization extensions (such as Intel VT or AMD-V), allowing for efficient CPU and memory management.
– KVM operates at the hardware level as a full virtualization solution. Since it utilizes the host’s hardware virtualization features, such as Intel VT-x or AMD-V, KVM can provide near-native performance for virtual machines (VMs).
OpenVZ:
– OpenVZ, on the other hand, is a container-based virtualization solution. It allows multiple isolated user-space instances, known as containers or Virtual Private Servers (VPS), to run on a single physical server.
– All containers share the same kernel, meaning that they are lightweight and have minimal overhead. However, this also means that they can only run Linux-based operating systems.
– OpenVZ provides efficient resource management and is ideal for scenarios where rapid scalability and minimal resource consumption are priorities.
– OpenVZ, on the other hand, is a container-based virtualization solution that allows multiple isolated Linux containers to run on a single host. Since all containers share the same kernel, OpenVZ often exhibits lower overhead compared to KVM.
Differences Between KVM and OpenVZ
First, the most basic difference between OpenVZ and KVM is that OpenVZ can ONLY host LINUX operating systems, while KVM is more flexible and can host Linux, Windows, and custom OS.
Both a pro and a con of OpenVZ is the complete sharing of resources it allows. OpenVZ uses a shared kernel with a layer of virtualization on top of the actual Linux OS. Since this kernel is shared by all VPS users on this node, the kernel is not customizable. Once you have hit your allocated RAM provided to you by the host, the remaining RAM becomes a free-for-all for users on the server. This is not a problem if you run small applications, but you may be in trouble if you are running something more resource intensive.
KVM allows you to set maximum and minimum values to your resources, providing you to use only the resources your applications need. This is true, real hardware virtualization, meaning better performance from lower requirements on the hypervisor. 100% of the RAM and disk resources are dedicated to one individual user. KVM provides a more isolated environment and gives users their own kernel.
The risk of overselling: Overselling is where a host will overcommit resources to certain accounts hoping that not every account uses up all those resources. While everything can be oversold, beware of shady hosting companies overcommitting OpenVZ systems and putting you on a system with too many containers. KVM can also be oversold, but it’s better isolated. Since OpenVZ hosts are often oversold, OpenVZ servers are typically a cheaper cost than KVM servers.
OpenVZ provides the end-user with speed and scalability, and it’s more affordable. KVM offers private virtualized hardware including network card, disk and graphics adapter, and guaranteed resources for increased reliability and customizability. KVM packages are ideal for serious resellers, game servers, small businesses, and medium-sized enterprises.
Resource Overhead:
KVM: As a full virtualization tech, KVM introduces some overhead due to each VM running its own kernel. This overhead can affect performance, especially for lightweight applications. However, for resource-intensive applications, KVM can effectively leverage hardware resources, resulting in strong overall performance.
OpenVZ: Because OpenVZ containers share the same kernel, they do not incur the same overhead as KVM. This allows for higher efficiency and faster provisioning times, especially for applications that require rapid scaling under peak loads.
I/O Performance:
KVM: KVM can achieve high I/O performance by utilizing paravirtualized drivers and direct access to physical hardware. It can efficiently manage I/O operations, making it suitable for applications with heavy read/write operations.
OpenVZ: OpenVZ typically provides excellent I/O performance, as containers can access the host’s storage directly. However, since all containers share the same I/O subsystem, I/O contention can occur if one container excessively uses I/O resources, leading to potential performance degradation for other containers.
NOTE: If you are a host selling to your clients, OpenVZ is easier to set up and maintain properly, while KVM takes much more networking knowledge. OpenVZ and their templates are more beginner-friendly in that aspect. If you are simply an end-user, don’t worry and go with a managed hosting provider.
We are excited to offer you top-notch KVM VPS and OpenVZ VPS hosting services that perfectly cater to your needs! Whether you’re looking for the high performance and flexibility of KVM virtualization or the lightweight and efficient nature of OpenVZ, we have solutions designed for businesses of all sizes.
Our KVM VPS provides dedicated resources and enhanced security, while our OpenVZ VPS ensures rapid deployment and seamless scalability. Whichever option you choose, you can count on reliable performance, exceptional support, and competitive pricing. Explore our hosting services today and elevate your online presence!
One reply on “KVM or OpenVZ which virtualization is absolutely better?”
OpenVZ all the way! KVM gave me nothing but problems, but hey that's just my experience.