In Move a Website to a New Server – The Easy Way, I looked at a simple way to move your website and email from one hosting company to another. This approach is fine for sites that don’t have too much user-generated content. However, if you run a busy site with lots of blog comments, forum posts, or customer orders then things can start to get messy with this approach.
Why? Well, when you move your domain to the new hosting company’s nameservers — a process known as redelegation — it usually takes a couple of days for the change to propagate around the internet. During this time, some visitors will be seeing your site on your old server, while others will be looking at your new server. This means that you’ll end up with new content being added to both the old site and the new site at the same time, which can be a major headache!
Fortunately, there’s a way round this problem. It’s a bit more fiddly than the “easy” approach, but it does result in a seamless transition. The great thing about this approach is that there will only be a few minutes where both the old and new servers are being accessed at the same time, as opposed to several days.