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

[VPS6.NET]

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...is-better.html

[mountainman]

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]

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.