Virtual Private Servers vs. Dedicated Servers for Web Hosts
Most web hosts start out on a shared server, which is one web server housing multiple websites, potentially from dozens or even hundreds of different clients. Shared servers are a good place to start but, at times, can be poor in terms of service, depending on the particular host, the sites that happen to be on that machine, and the number of sites that the host allows on the machine.
All resources on the server, such as memory, hard drive space, processor speed, and so on, are shared between all the websites on the machine. This means that if one site gets too busy or starts using large amounts of the server’s resources, all the other sites on the server suffer.
You can avoid this by using a Virtual Private Server (VPS) or dedicated server for your site instead.
While shared servers have shortcomings, there are many hosts who do an admirable job of balancing the need for lots of sites to be on the server to keep costs down with ensuring that the servers perform well. Don’t be afraid to use a shared server until your site gets too big for it.
The major difference between a VPS and dedicated server comes down to the V (for virtual) in VPS. A VPS gives you your own server with its own resources, but only a virtual one — meaning some software is running on a physical server that splits it up into a number of theoretical pieces and assigns an amount of resources to each of those pieces.
It’s like cutting a pie into slices; when someone comes to take a slice, he just takes the piece you’ve cut for him without disturbing the rest of the pie. A common way to do this is for a server that has, say, 8GB of memory in it to be split into four VPSs, each of which is given 2GB.
The virtualization process works fairly well, and for the most part you have your own small, self-contained server. In theory, each VPS can access only the resources allocated to it, but in practice, many are set up to allow some overflow — that is, to steal resources from other VPSs on the same dedicated box.
This means that although in theory you are guaranteed to have, for instance, 2GB of RAM, if another VPS on your server gets really busy it might steal some of your memory and processor time.
Although a VPS is a much cheaper option than a dedicated server, if you expect to significantly grow your site, it may be a false economy. The nature of a VPS as a virtual server created by partitioning off a physical server means your upgrade options are limited.
Servers can only have so much in them physically to start with, and, if your needs expand, a VPS might not have the resources available for you to expand into, which means that a scary, time-consuming move to a dedicated server might be necessary.
Dedicated servers, on the other hand, are servers you purchase (or lease) for yourself that give you a guaranteed amount of resources with nobody else able to use the server or able to "share" any of your resources. A dedicated server is a physical box in a rack in a data center somewhere; it is physically, individually yours.
Obviously, it is considerably more expensive to have your own personal server than shared or VPS hosting, so there are three main factors to consider when choosing between the types of server:
Cost: Shared hosting is by far the cheapest. VPS is considerably more expensive (five to ten times the cost). Dedicated servers are normally at least three or four times as expensive again.
Mission criticality: Deciding how important it is to have your website always available and always running at the fastest possible speeds is important. If you have a blog about things you find between your toes and you're making no money from it, it isn’t important that your site is always available. If you're running an Internet-based business, every second your website is down means reduced sales and lost revenue.
Website traffic: If your website's traffic consists of your mother coming by once a week to find out what you're up to, then you're safe to use a shared server. The more visitors you get, however, the higher up the server scale you need to go. If your traffic is increasing rapidly and you expect it to continue, a VPS or dedicated server may be what you require.