VPS, VDS and PDS: What’s the Difference?

As with any technical area, web hosting has many acronyms that can be confusing to the layperson. In this article we attempt to explain some of the differences between some common types of hosting solutions, and show you what the pros and cons of these are.

Let’s start by explaining what these acronyms stand for:

  • VPS – Virtual Private Server
  • VDS – Virtual Dedicated Server
  • PDS – Physical Dedicated Server

As you can see – these are all ‘server’ web hosting services that are available. However, picking the right solution for your requirements is not so easy – you don’t want to end up with a system that is underpowered for your requirements, nor do you want to be paying too much for a service you will only ever use a fraction of.

Before selecting a hosting service, it is important to understand the key differences between these types of services.

VPS – Virtual Private Server

A ‘VPS’ is often a cheap way to get started with website hosting, and is a step up from ‘Shared Hosting’ (where your website sits on a server with hundreds or even thousands of other sites). As the name implies, the server is ‘private’ – in that only your website(s) are on the server.

The server is ‘virtual’ meaning that it is not a physical server that is assigned to you, rather a partition of a physical server is assigned for your use. Typically VPS services use an ‘Operating System Level’ virtualisation technology such as OpenVZ.

The benefits of this hosting service over shared hosting is that you get a lot more freedom to do what you want with your server. Generally you are provided ‘administrator’ or ‘root’ level access to the server, and can configure it (or have it configured) exactly as you need. Want to change the PHP settings or install a new module? You can easily do this with a VPS.

This technology also allows a web host to provide many ‘VPS’ clients from a single physical server. The downside to this is that the service may be subject to overcrowding – where too many VPS customers are on the one host server (node). This can result in a situation where if there is a problem in a VPS that runs on the same node as yours, that your VPS can be affected – either running slowly or worse – completely offline!

VPS Servers are best used for websites that are starting to outgrow typical shared hosting – e.g. your blog is increasing in popularity and is starting to take a while to load, or if you need to install custom server modules or have other complex requirements.

VDS – Virtual Dedicated Server

The VDS service is the next step up the ladder from VPS in terms of performance, reliability, and of course, price. A VDS service will provide the same benefits as a VPS over Shared Hosting, however the Virtualisation technology that is used to deliver the service is very different.

The virtualisation technology used to deliver VDS services are typically ‘Type 1’ Hypervisors such as VMware ESX or Microsoft Hyper-V. This virtualisation software runs directly on physical servers (whereas with VPS servers, the virtualisation runs on top of the server operating system), and is typically configured in Clusters. The virtualisation software has a management component that continually monitors the health of the host (node) server in the cluster and can react to server outages to provide a highly-available and/or fault-tolerant service.

The key benefits linked to this type of dedicated server hosting, include enhanced performance, scale and reliability. The performance of a VDS is typically higher than a VPS, as there are less computing layers in the VDS model, meaning that requests for resources (e.g. access to the hard disk) by your server have a shorter distance to travel to be serviced. The virtualisation technology is designed to be able to run very large virtual servers, so these services can typically scale up with your resource requirements very easily. Lastly, due to the built in fault-tolerance and high-availability features of the technology, VDS services are typically much more reliable as they are able to ‘self-heal’ in the event of a physical server failure.

VDS servers are best suited to medium to large sized websites – and in particular e-Commerce sites that often require a significant amount of resources to run quickly. They are also highly recommended for web design companies that want to host their client’s sites.

PDS – Physical Dedicated Server

Lastly is the PDS option (or Physical Dedicated Server, a.k.a. Physical Hosting). This service involves your web hosting company setting up a full physical server (with its own CPU, memory and hard drives) solely for your use.

The primary benefit associated with this service is that you share basically nothing (other than access to the internet) with anyone else – you have the whole physical server to yourself.

Having the whole server’s resources to yourself might sound like the best option available, however there are a few points to consider:

  • Reliability: Your one physical server is significantly more likely to experience a hardware fault and be offline, then to have an outage with a VDS service. Additionally if replacement hardware parts are required, your server may be offline for many days waiting for repair.
  • Scale: You have all of the resources of the server at your disposal. However, when you outgrow the server, you may need to buy an entirely new server, then manage a site migration – this process can be costly and time consuming. A VDS service is elastic – the resources can grow and shrink in accordance with your business needs.
  • Cost: Having all of the resources of a physical server isn’t cheap. Up-front and ongoing costs are likely much higher than that of an appropriately sized VDS server. This is possible due to economies of scale with the hosting provider.

Physical Servers are best for companies that have linear requirements for hosting (e.g. an application which will not need more resources over time), and in particular those that know how to properly manage the physical hardware.

The wrap up

There are quite a few differences between these hosting types that need to be considered before your next investment in web hosting. Identifying your current business needs as well your long term requirements will help you choose the optimal hosting service.

email

Comments are closed.

Post Navigation