Shared hosting allows thousands of people to host their own sites at a very reasonable cost. It has some drawbacks, however. Since hundreds of sites can be hosted on a single server resources such as CPU, disk space, and bandwidth have to be shared with your virtual neighbours.
Shared resources are usually not a problem for small to medium sized sites. Your main limitation is the lack of control over system level software – http servers, mail servers etc. You don’t have any choice of operating system and you cannot compile programs or do administrative tasks such as setting up Spam filters or firewalls.
Many people would say ‘So what? I don’t want to do that stuff anyway!’ It’s true that the majority of website owners have no interest or ability to handle this kind of work and are happy to leave it to the hosting company. Those who desire more control over their server environment or wish to experiment with new software, however, can get access to this level of management with a Virtual Private Server.
A virtual private server (VPS) is a physical server that has been divided (using software) into several virtual machines, each acting as an independent dedicated server. The physical resources such as RAM, CPU and disk space are still shared, but each VPS acts independently of the others. Each VPS can have a different operating system and can be configured in any way possible.
The key advantage of VPS is allowing each VPS administrator access to the root level of his virtual server. This kind of access allows the administrator to install and delete software, set permissions, create accounts – in short, do everything that the administrator of a ‘real’ sever can.
As well as providing more control over your hosting environment, a VPS is more secure than shared hosting. Websites on a shared server all have the same operating system, so if a hacker were to find access to the root of the server he could damage any or all of the websites on that server. A VPS, on the other hand, is divided in such a way that even if a hacker were to gain entry through one account, there is no way to access the others. Each VPS is invisible to the others and there is no way to set up root level access from one VPS to another.
Virtual Private Servers can be set up in various ways so be sure to understand how the hosting company has allocated resources. The most common configuration is to divide all the physical resources evenly by the number of accounts. Thus, if there are 10 virtual servers, each would receive 10% of the total bandwidth, CPU, memory and disk space.
The disadvantages of VPS are almost the same as the advantages. The control that a VPS account provides can be dangerous if you don’t know what you are doing. You have the ability to delete files, set permissions improperly, allow virus-laden software on the system and, in general, really screw things up. If you don’t have the knowledge to administer a server, or are not willing to learn, VPS is not for you.
If your website has outgrown shared hosting, however, VPS offers an affordable alternative to dedicated hosting. When shopping for a VPS host, be sure to find out how system resources are divided up, the number of VPS accounts on each physical server, the method for upgrading, and the choices of operating systems.