Question: I have my own domain name. I want to move my site from one host to another retaining the same domain name. How can I do this whie still having my site available throughout?
Answer: After you move your site it will take a while before the various domain name servers are updated to reflect the new location of your site. Most will be updated within a few days but some might take longer. I suggest that to best maintain your site availability throughout the move that you perform the required steps in the following order:
Performing the steps in this order will maximize the availability of your site throughout as everyone will be able to access either the old or new location of the site. The only disadvantage of performing the steps in this order is that you end up with about a month where you need the site to ba available in both locations which results in increased hosting fees for that period. Unfortunately if you want everyone to still be able to access your site during the move there is no option but to have an overlap in the hosting. The majority of domainname hosts get updated at least weekly so if having a small percentage of your visitors unable to locate your site for a few weeks doesn't worry you then you may find a weeks overlap to be sufficient but too properly maintain the availability of your site, I recommend that you maintain the old site for at least three weeks or longer.
This article written by Stephen Chapman, Felgall Pty Ltd.