VPS Hosting

VPS Hosting

VPS stands for ‘virtual private server’ and is a type of hosting that can be categorized under both shared and dedicated hosting. VPS hosting works by splitting the resources of a physical hosting node amongst VPS; the number of VPS which you can fit on a node is dependent on the node’s resources. The result of the resource splitting is several VPS which have their own dedicated environment; all VPS have a guaranteed amount of RAM, disk space and bandwidth, but the CPU is shared amongst the VPS on the node. VPS are seen as the fill in for the gap between standard shared hosting, and dedicated servers; this is book you are given your own dedicated environment as you are with a dedicated server, but the CPU is shared with other users who are on the same node as you. Also, VPS packages tend to be a bit more expensive than a standard shared hosting package, but less than a dedicated server. With most VPS servers, you are able to choose any operating system that you want to use; in some cases you are also able to choose the size of the data pipe that you want to use, but options such as the amount of RAM and disk space assigned to you cannot be changed meaning that if you want more, your only choice it to upgrade to the next package. If you are on a shared hosting package, but your needs point more towards a dedicated server, but don’t have the funds then a VPS might be what you need; VPS are currently available mainly on Linux and Windows platforms.

Operating System Choices

With a VPS, you are limited to your choice of OS by the OS that the node is running; for example, if you have a VPS on a node which is running Windows Server 2003, you can only have Windows Server 2003 as your operating system, and if you have a VPS on a node which is running Linux then you can only have a Linux distribution as your OS. Most hosts allow you to install what OS you want, since you are normally provided with a control panel which you can use to reload your VPS to any operating system template which is in the host’s system; however, most hosts do not allow the reloading of Windows servers since it must be done manually by the host themselves. The use for your VPS should always be reflected in the choice of OS; for example if you want to host an ASP.NET web application, you should choose a Windows VPS, and if you want to host a PHP/MySQL based web application, you should go for a Linux based VPS. Your choice of operating system might also be affected by the specs of your VPS; for example if you have a VPS which is meant to be Windows based that only has 64mb RAM, then you won’t be able to run Windows since the minimum RAM requirement for Windows Server 2003 is 128mb.

Resources

All VPS are allocated a certain amount of RAM, disk space and bandwidth. RAM comes in two different types within VPS – guaranteed and burst; guaranteed RAM is the RAM which is uniquely assigned to your VPS and cannot be used by anyone else and is always there for you, burst RAM is RAM that is shared amongst all the VPS on a node and is utilized by a VPS when it runs out of guaranteed RAM. VPS which hog the guaranteed RAM or who carry on using it for a long time at the expense of other users may be shut down by the VPS software, or might just crash themselves. Disk space which is assigned to a VPS is exclusive and can only be used by the VPS to which it has been assigned. Bandwidth that is assigned to a VPS is again, exclusive meaning that it can’t be used by any other VPS hosted on the same node; most hosts allow you to purchase extra bandwidth, but it is quite expensive since it is a treasured resource. The CPU on a host node is not split amongst VPS like other resources; it is instead left how it is so that the VPS can use as much of it or as little of it as they want – VPS which use too much of it will be shut down automatically by the VPS daemon.

Uses

Due to the fact that VPS are somewhat ‘isolated’ environments on the physical node, they are commonly used for testing (sometimes known as sandboxes) for applications, so that if any problems are found they don’t harm the main node. Due to the fact that you have your own dedicated environment, you are able to install most programs of your choice, however this may be dependent on the resource specifications of your VPS; some software such as firewalls and anti-virus clients don’t run well within a virtual environment. Unsurprising, the virtualization software itself doesn’t run well within a virtual environment itself; for example, some people have tried without success to create VPS within a VPS – the main let down being that the performance decreases as you go through virtualization layers. VPS servers are sometimes referred to honeypots – the term that is given to the action of running a piece of software with known security flaws; these are run within VPS environments since if there are any problems with the software, then the host node is unlikely to be damaged.

VPS Software

All VPS need virtualization software to run them – this software can either come at a very high price or cost nothing at all. The main pieces of virtualization software that are run by web hosts are Virtuozzo by SWSoft which can run on both Linux and Windows, but comes at a high price tag, and OpenVZ which is an open source alternative to Virtuozzo for Linux, and costs nothing. Another solution which is used by large corporations as well as home users is VMWare, which is available for Linux, Mac and Windows and allows you to create multiple virtual environments from your desktop.