A Virtual Private Server (VPS) or Virtual Dedicated Server is a simulation of hardware by a host operating system that allows another operating system to run on it

Each virtual server is isolated from the others (or "Private"), and access to hardware resources (RAM, CPU, Disk Space, Network throughput) is managed by the "host" server. So, for instance, a server may have 2GB RAM, 100GB of disk space, and 2 x 2GHz processors, with 10 VPSes on it. Depending on the VPS software that's used on the host machine, each VPS can either share hardware resources, or have guaranteed access to 200MB RAM, a disk space limit of 10GB, and an effective CPU of 400Mhz. Now, this is a slight oversimplification, but it gives you an idea of a potential VPS scenario. Our servers at bare minimum consist of Dual Xeon, 12GB Ram and 2TB storage or connected to a storage array.

Is a VDS/VPS Hosting Right for Me?

VPS/VDS hosting plans fill the gap between entry level Web hosting plans that offer specific services (such as PHP/MySQL, or Perl/CGI) with a limited amount of disk space on a shared server, and co-location, where you own and manage the hardware and simply rent "rack space" and an Internet connection from a data center. If you're outgrowing a shared hosting plan, but aren't ready for the financial commitment of co-location, a VPS hosting plan could be the ideal middle ground.

VPS hosting plans offer the following key advantages:

• root access gives you the ability to install and configure any programs you want. Want to run PHP with PostgreSQL instead of MySQL? Go ahead: install it. Want to try out Zope/Plone? Knock yourself out.
• You can host an unlimited number of Websites through Apache's Virtual Hosts.
• You can host other services, such as a mail server, an FTP server, or any type of server you want.
• You can use the server for backup, file storage, or anything you need.

How Does it Work?

A number of virtualization technologies make Virtual Private Servers possible: there are commercial companies, such as VMWare, and Microsoft's own Virtual PC, Open Source offerings such as User Mode Linux, QEMU, and more recently XEN. This is a hot topic in the Linux world at the moment, with XEN, in particular, receiving a lot of press and support.

Getting to the Root

So what do you get with a VPS account? Well, the one thing you do get is root access to your server. As mentioned above, if you're comfortable with administering a Linux server remotely, this is, of course, a great thing. It means you have complete control, can install any programs you want, and do anything you choose. However, it also places the responsibility for configuration and implementation in your hands. If you're not comfortable with this, stay away from VPSes.

Does that mean you need to install the entire operating system from scratch? Probably not. Most VPS plans have a number of "disk images" to choose from, with different distributions (such as Debian or Fedora Core) in default configurations. You simply specify which disk image you want, and it will be configured on your VPS in a matter of minutes. Once you are set up with an account, you are then given root access via ssh, and can log in and customize your server, install new software, remove unwanted software and update existing software as needed.

If you have a small budget but big ideas, a VPS may just be for you.