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Virtual Private Servers (vps) - a Guide

by Ewan MacLeod

Web Hosting, if tarred with as broad a brush as possible, is split into Shared and Dedicated Hosting. There are those who purchase a space on a server for their own use, and then there are those who just buy the server. A bit like buying a plane ticket, or buying a plane (except the difference between a return to Oslo and a Cessna are a bit more pronounced).

There is a bridge over these troubled waters, however. It’s known as VPS (Virtual Private Server – it’s also known as VDS, Virtual Dedicated Server, but that’s not as common, presumably because it leads to confusion with old fashioned displays and sounds like something unsavoury you might catch on a night out in Calcutta). VPS allows freedom from the constraints of Shared Hosting, without the expense or expertise of a Dedicated server.

A Shared Hosting server typically has an operating system installed on it, and the host then installs the software they want – they set the server exactly as they like it, and then customers pay them certain amounts of money to purchase a little space on the server. The customer has as much control over that space as the host will let them, and their performance will be based on however many customers are Sharing the server (hundreds, perhaps). Remember that a server is just like your computer at home or at work – and just like your computer, it has a certain amount of memory and a certain speed of processor, and it can only do so many things at once before it has to start putting people in a queue (this is the point where your site may seem slower than usual).

A Dedicated server works the same as a Shared server, except the owner of the server has far more control over what is on their server. Like the hosting company with the Shared server, the owner of the Dedicated can pick the operating system, what software is installed, and how many sites run on the server. If a Dedicated server is set up specifically for one site and is configured for that site alone, that site will run considerably faster than a site on a Shared server. It doesn’t have to share resources and it can be built purely for the purposes of running that site.

VPS sits between these two types of hosting. There are several kinds of VPS, but we will focus on software VPS. In this instance, the host will buy the server, and install an Operating System (OS) on it. They then use another program (i.e. Virtuozzo) to create several isolated Virtual Servers (sometimes known as Containers) on the server. Each of these Containers is a Virtual Server – they function as if they were stand-alone, Dedicated Servers, when in actual fact they are a more advanced form of Shared hosting!

Compared to Shared hosting, VPS has many benefits. To begin with, Shared hosting comes with no performance guarantees. That’s not to say that Shared hosting is slow – it’s just that some sites require a lot more resources than others, and a few busy or intensive sites on a full Shared server could well impact the performance of everyone else (try opening a few basic programs on your computer at once , keep them open, and then see how well your computer runs when you start a virus scan – those basic programs aren’t so responsive now, are they?).

With a VPS, your Container will come with a guaranteed proportion of the server’s resources. This usually comes in the form of RAM (Memory) available – for instance, your VPS might come with a guaranteed 256 or 512 MB of RAM. This means that, regardless of how many people there are on the server, regardless of how busy their sites are, you always, always have that much memory available for you to use. Some companies also advertise the ‘burst’ memory available to you as well. This is essentially the memory that you could conceivably use, assuming that everyone else isn’t using their quota. However ‘burst’ memory is a subjective term – as there are no guarantees on how often this memory will be available to you (beyond the length of a piece of string), it’s more a fancy figure to impress potential customers with.

As a Container is purchased with a guaranteed RAM quota, there will be far fewer customers sharing a VPS server than there would be sharing a, er, Shared server. So the CPU won’t be divided between as many clients and their respective demands on it, so speeds will improve and the load on the CPU will decrease. All in all – your hosting will be noticeably faster. Again, some hosts will advertise CPU preferences, server contention rates etc., to demonstrate how the more expensive VPS packages will take preference to some degree over the cheaper packages when requesting resources from the CPU. How much this makes an impact on your decision to buy that VPS or not is up to you; many hosts don’t make any preferences between packages whatsoever.

The other major benefit to a VPS is the extra control that you will have over your hosting. If you’ve managed to find someone who does hardware VPS, then you’ll be able to pick your own OS as well (hardware VPS, essentially, creates the VPS on a hardware level rather than a software level – the good part; you can do whatever you like with your VPS – the bad part; the hardware, rather than shared, is divided, so instead of having the use of, for instance, a 2gHz processor and a guaranteed 256MB of RAM, you get a .5gHz processor and a guaranteed 256 MB of RAM if 4 people are sharing your server). From here you can configure your hosting as you see fit – customise your PHP settings, install PHP x, Zend whatever, Hardy Heron and/or Peggle (not recommended for a work environment). Even better, as your VPS is essentially a Virtual Machine, you can take snapshots of your entire VPS – so your whole account can be backed up into a single file, and then should something go horribly wrong, you can use the snapshot to restore the VPS in its entirety.

VPS will, of course, cost more than Shared Hosting, but on the flip side of the coin it is considerably cheaper than a Dedicated server. If performance is more of an issue for you than cost then a Dedicated is the way forward – a VPS will never be able to command the amount of resources that a Dedicated server used for the same purpose can. But as a cost-effective solution to providing a significant performance boost to your hosting, as well as allowing yourself a greater degree of control – VPS is hard to fault.

*Please note - I’ve been to Calcutta. I’m not implying that the place is unsavoury, disreputable, or otherwise trying to smear the good name of Calcutta in any way - it just seemed to round the sentence off nicely!

About the Author:

Ewan MacLeod works for NuBlue, a UK based Web Agency that specialises in Web Design and Web Hosting.

Monday, Aug 18th, 2008