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View Full Version : OpenVZ vs. Xen: What's the difference, and which is better?



VPS6.NET
01-02-2012, 06:48 AM
We've written this article to provide a little insight into the difference between OpenVZ and Xen, two very popular but somewhat different virtualization technologies. Ultimately, as with choosing between a Linux or Windows server, you will need to think about the applications you will be running to decide whether OpenVZ or Xen will be a better fit for them. Below is a brief overview of some of the key differences between these two platforms.

The slightly more reliable virtualization software is Xen, a para-virtualization platform that creates VPS with almost exactly the same characteristics as dedicated servers. A Xen VPS will run its own isolated kernel, load its own kernel modules, use fully dedicated virtualized memory, I/O and scheduler, and will be just as stable and customizable as a dedicated server. For a small premium, you'll never know that you're only using a virtual server.

OpenVZ, on the other hand, is an operating-system-level virtualization platform that works in much the same way, but provides only a thin layer of virtualization on top of the underlying OS. All VPS on an OpenVZ node will share the same core Linux kernel--this is why OpenVZ only supports Linux systems--, and, consequently, will also suffer alike from issues like kernel crashes. Despite these small drawbacks, OpenVZ VPS are more cost-effective, easier to understand, and are usually much more effective than Xen as cheap VPS, due to having the extra resources available that a Xen VPS would be using to run its completely isolated environment.

Certainly, these are not the only differences between the two platforms, but they are some of the most significant:

Main Features of OpenVZ Virtualization:

Full root access.
OS-level virtualization.
'Burst' RAM and other extra resources available when nodes are underused.
Upgrades can be applied on-the-fly, without reboots.
More resources available due to lightweight virtualization.
Simple network and disk setup.
Access to most iptables modules.


Main Features of Xen Virtualization:

Full root access.
Supports Linux and Windows.
Better Java performance.
Resources (RAM, etc) are fully dedicated and private.
Para-virtualized Linux kernel (i.e., full isolation).
Direct access to loadable kernel modules.
Swap space.
Highly configurable.


If you are unsure which platform would be better for you, an OpenVZ VPS will most likely be an easier and more cost-effective solution, unless you already know that you will require specific kernel modules that OpenVZ does not support.

From our Knowledgebase: https://vps6.net/my/knowledgebase/12/OpenVZ-vs-Xen-Whats-the-difference-and-which-is-better.html

mountainman
01-02-2012, 11:31 AM
I am slightly confused between choosing an OpenVZ or Xen VPS, linux of course. But i prefer Xen because as you said it's a separate kernel. Since OpenVZ uses a shared kernel it can sometime cause issues.

AdrianG001
03-18-2022, 05:56 AM
Compared to Xen, OpenVZ actually requires both the host and guest OS to be running Linux. This is because OpenVZ uses a single patched Linux kernel, but since it doesn't have the overhead accompanied with legitimate hypervisors it's super-fast and extremely efficient.