Avoid down time, seamlessly transfer hosting with no interruptions

Here is a HostGator article which explains how to avoid downtime.

Advanced Techniques

We have also included some advanced tips below to supplement and expand upon the article linked above. There are multiple techniques for avoiding downtime when transferring websites, and you will want to choose the method most appropriate for you and your site. Some methods are more technical and/or require more attention than others.

What about my Database?

Your database(s) will be copied over to the new server as part of the transfer process. If your database does not change much (for example, it only changes when you add new posts or pages to your site), then there is little risk of lost information during the transfer process.

On the other hand, if you have a website where the database in constantly being updated with new information, such as forums or a site with lots of user generated content, you will want to take special care to make sure no information is lost in the transfer. There are a couple ways of doing this.

Advanced Technique 1: Reconfigure the site on the old server to access the database on the new server prior to changing the DNS.

One way to do it is you can configure your site to connect to your new database, remotely; this way whether your visitors are directed to the new site or the old site, all the new updates will be saved to the new database. Now the new database will have all of your current information and can continue to update.

This technique is the most technical, but would minimize downtime as much as possible for all visitors to your site. You or your web designer would need to make changes to your site during the transfer to make this work.

A simplified set of steps include:

1. Transfer all the files, databases and other settings over to the new server. (Via free content transfer or you transferring the files yourself.)
2. Test the site on the new server to make sure it works as expected.
3. (If changes have occurred to the database between steps 1 and 4, then re-transfer the most recent version of the database. This step is unnecessary if you do step 4 immediately after steps 1 & 2.)
4. Change the database settings on your site so that the site on the old server accesses the database on the new server.
5. Change the name servers and DNS to point to the new server.

Using this technique, it would not matter which server a visitor sees while the DNS propagates, since both the old server and new server update the same database.

Advanced Technique 2: Disable updates to the database on the old server during the transfer.

Another method is to modify your website on the old server so that it does not accept updates to the database during the transfer. Like the previous technique, you or your web designer would need to make changes to your site during the transfer to make this work.

This technique is best if you are rapidly progressing through the steps necessary to transfer, and/or don't mind if a couple people temporarily see the old site while the DNS changes propagate. This is also good for sites where the database does not change that often because of user input.

Depending on how your site is coded, this could mean putting the site into a read-only mode where people can view information but not make any changes, turning on maintenance mode on your blog or CMS, or possibly disabling the database all together and putting up a temporary page telling customers the site will be up shortly.

Ideally you would do this immediately before transferring the latest copy of the database over to the new server, and once that is completed, changing the name servers and DNS to point to the new server.

While the DNS propagates (updates) worldwide, some people will see the site on the new server, and some will see the site on the old server, yet only the new server will accept changes in the database.

A simplified set of steps include:

1. Transfer all the files, databases and other settings over to the new server. (Via free content transfer or you transferring the files yourself.)
2. Test the site on the new server to make sure it works as expected.
3. On the old server, modify your site so it cannot accept changes to the database.
4. (If changes have occurred to the database between steps 1 and 3, then re-transfer the most recent version of the database. This step is unnecessary if you do step 3 immediately before or after step 1.)
5. Change the name servers and DNS to point to the new server.

While the DNS propagates worldwide, some people will see the site on the new server, and some will see the site on the old server.

Tips on Reducing Propagation Time

After the content transfer, you can create an A record in your existing DNS (most likely on your old server) to redirect all visitors to the new server; this is much faster than waiting for the propagation of new name servers.

Also, after the site transfer, you can create a MX record so your emails will all be delivered to the new server and not need to wait as long for propagation.

Once you have the A records and MX records updated to point to the new server, you can change the name servers anytime.

Transfer Time Frame

We require up to 72 hours for all transfer requests. The time will depend on how large is your transfer. (If you need the content transferred faster, or need more control of the transfer process, you may transfer the files yourself instead of having us do it.)

The free transfer service does not include any programming, code or configuration changes to your site that would need to be made in the advanced techniques described above (for example, changing your database settings on the old site so both point to the new database, or name server changes).

Basically, the more control you want over the transfer process, the more involvement would be required of you or your web designer in the process.