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.
, 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:
Main Features of Xen 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.
- 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.
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