Why we use Dedicated Servers?


Snoopy Pfeffer's picture

By Snoopy Pfeffer - Posted on 11 March 2012

Virtualization Technologies

When you have a look at other OpenSim hosting providers, you probably recognize, that most use Virtual Private Servers (VPS) or Cloud Hosting Services as basis for their offers. Some providers even do not mention what kind of hosting they base on, where you can expect that they use some cheap VPS for OpenSim.

VPS as well as Cloud Services are virtualization technologies that implement an additional layer between the applications and the underlying hardware platform. The goal is to achieve higher hardware utilization and flexibility. The basic assumption is that costs can be reduced by sharing expensive hardware resourced by as many users as possible. Depending on the applications used, this is good method to reduce costs.

Applications Suitable

Typical applications VPS and Could Services are designed for are applications like web or email servers, that can be swapped to a slow hard disk and kept asleep until they are needed. When needed these applications are loaded back into memory and executed, until the application can be put asleep again. This way only currently active web sites need expensive processing and memory resources.

The timing requirements for web and email applications are less critical. When a web server restarts, it is OK when the response is sent with some delay. It is also no problem for such applications to reduce computing performance or the available network bandwidth, if the underlying hardware platform currently experiences high utilization.

The foundation of providing an application less resources than needed is the so called Fair Use Principle. If one application uses too many resources (CPU, memory or bandwidth) measures are taken to ensure that the overuse of one application does not affect the service quality of other applications. This can mean that the available bandwidth is cut back or that the processing power is reduced, to ensure no other application is affected negatively by that overuse. The basic assumption is, that throttling does not seriously affect the service quality users experience.

Applications not Suitable

Other kinds of applications are less suited for virtualization technologies. Real time applications like Internet or video telephony or virtual world applications are applications that should not run on any virtualization platform. There are various reasons why such applications cannot run on virtualization platforms with good service quality:

  • Virtual world applications constantly need processing power and cannot be put asleep
  • Enforcing the Fair Use Principle causes throttling of the use of hardware resources
  • Swapping does not support sudden high peaks of processing power or network traffic
  • Not enough computing power is provided when needed, because of shared resources
  • Virtualization platforms are not designed for real time applications

With only 1 or 2 avatars online and not too much built on your OpenSim region, you can be lucky, when the underlying hardware server platform is not fully utilized yet. In that case VPS or Cloud based OpenSim hosting can be a cheap alternative for you.

In the case you expect more visitors or if you build more on your OpenSim region or if the virtualization platform provider connects more and more customers to his platform, to increase utilization and thus his revenue, you will experience serious problems running OpenSim on that platform. Service quality will drop, you will experience lag and sometimes even viewers of visitors will crash, because responses were not received on time.

In such situations your OpenSim process is constantly put asleep and reloaded or at least gets throttled, because resource usage contradicts the Fair Use Principles of typical applications such virtualization platforms are designed for. The bursty nature of OpenSim network traffic can cause additional problems. The more memory your OpenSim region uses, the worst will be the delays and thus bad effects on service quality.

Conclusion

This is what a CTO of a big VPS hosting company once told me:

“VPS is not suitable for any real time application [voice, video streaming or virtual worlds].”

We strongly recommend to just use dedicated servers for OpenSim. At Dreamland Metaverse all OpenSim regions and grids are run on dedicated, high performance, multicore servers, which are optimized for OpenSim.

We want to be sure that you have a top quality service experience!