KVM VPS vs. OpenVZ VPS: Which one is better?

In most of the cases, people use shared hosting when they start an online business. Shared hosting is a cheap option and will not let you down unless you are using huge amounts of traffic. However, the problem is that your website can overgrow the shared hosting account one day and you will have to opt for a VPS webhost.

What is a VPS?
VPS is the abbreviated form of Virtual Private Server. This means that one machine is separated into different partitioned servers which will cover most of the features of a dedicated physical server. It is similar to shared hosting in terms of that a single server is split into multiple accounts. Nevertheless, the VPS account holder sees only their own virtual environment and can use the server as if had a dedicated server. If you own a website that needs to stay responsive 24/7, VPS is a good option to maintain it.

KVM VPS vs. OpenVZ VPS

This is a common question that surfaces regularly on the VPS market, so in this article, we will present a brief description of the main differences between the two technologies.
OpenVZ and KVM are both mature technologies with their pros and cons. Choosing the most suitable technology according to your hosting needs will help you save time and money. To help you understand which visualization system is more appropriate for you, we have presented the main features and benefits of them.

KVM VPS

KVM, or Kernel-based Virtual Machine, is a hardware virtualization technology on Linux core. This means better performance with fewer requirements from the hypervisor. KVM VPS uses free licenses and distributes the resources fairly among users. It doesn’t have burst resources, unlike OpenVZ. KVM VPS is the closest to a dedicated physical server. It gives you the opportunity to set limits for the resources, allowing you to manage them for the applications you need.
KVM stimulates hardware, meaning that it can be run on any kernel. Because the kernel is independent, the VPS can make its modifications to it, which gives the account owner a more isolated environment. OpenVZ, however, runs on Linux Kernel only, which limits its range of use. Nevertheless, KVM may require manual operating installation in most cases.
KVM VPS is a more flexible technology: it can host different OS such as Linux, Windows and other.

OpenVZ VPS

Unlike KVM, OpenVZ is an OS-based technology, which is based on Linux core. In other words, the host operating system is separated into partitions with different resources, each of which is assigned to their instance.
OpenVZ uses two kinds of resources, which are dedicated and burst. Dedicated resources are your own resources, which means you are guaranteed to have your own VPS. Burst resources, however, are a result of spare capacity in the system. This means that one VPS can temporarily use the resources of another when they are not being used by the latter. However, when there are no spare resources, the server can terminate processes running on burst resources.
The main advantage of OpenVZ is that it doesn’t need as many resources as KVM thanks to OS level virtualization. Unlike KVM, it doesn’t do full emulation and can share a kernel between various VPS-es which results in saving memory and CPU.
OpenVZ guarantees the lowest price for a VPS. It also causes lower management complexity for its users. For an entry level, OpenVZ is a good choice. However, when a shared kernel failure takes place, it affects all the VPS instances that run on the same server. Another disadvantage to OpenVZ is that it only runs on Linux.Despite some cons listed above, OpenVZ is less complicated to maintain and set up, while KVM requires more networking skills. OpenVZ has more user-friendly templates for hosting.
We have also included a table with the main features of two technologies to summarize what we listed above:

  OpenVZ KVM
Disk Resize Yes No
Low Overhead (shared kernels have lower overheads) Yes No
Support ALL OS No Yes
True VM Isolation No Yes
Disk Cache Yes Yes

Conclusion
Taking into account the benefits and disadvantages of the two technologies presented here, we can conclude that for more independent hosting solutions and for most efficient service KVM is the best. However, if the websites are not going to use many resources, you can opt for OpenVZ, which is also more affordable in price.

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