Subdomain to Main Domain Site Migrations
John Mueller of Google was asked about migrating a subdomain to the main domain. His answer explained why this type of site migration is difficult to do. Make it clear what to look for in order to increase the chances of success.
Move from the sub domain to the main domain
The person asking the question shared basic information that the sub-domain of the site has been around for decades. She explained that it is the most important part of the site.
Since this section of the site is so important, she was concerned about avoiding any negative impact from migrating the content of the subdomain to a new site within the main domain.
She also mentioned that the topic of the sub-field was politics and everyday issues such as public health policy.
John Mueller’s answer focused on what to watch out for in general about moving from a subdomain to a parent domain.
However, the last part of his answer consists of additional tips related to the Google News side of publishing.
Subdomain Migration: It’s hard to know the exact result
John Mueller paused for a moment to think about his answer.
His measured stance gave the impression that the answer was complex and that he was taking a moment to organize the best way to answer the question.
John Mueller paused to think about his answer
When he answered, Jun paused several times, again giving the impression that this was a difficult question to answer.
It may be because the main point of his answer was that the outcome of a sub-domain of a master domain migration is more uncertain than a one-to-one site migration from one domain to another.
John Mueller replied:
“Um… I… I think you can do it
So…let me see…uh…
Look… I think…
One of the key aspects here that uh… is important here when you move from a subdomain to the main domain, to a different directory for example, is that we need to look at the new website in general and kind of re-evaluate the overall situation.
This means that it is difficult to know ahead of time exactly what will happen.”
I think it’s important to stress that the problem with subdomain migration to the main domain is that, according to John, it can lead to a re-evaluation of what is now, according to Mueller, a new website.
Whereas in a one-to-one site migration, there is no need to re-evaluate the entire site because the site remains the same.
Subdomain Migrations: It’s hard to tell exactly
Mueller continued with his answer, emphasizing that the result of a subdomain migration to the main domain can be hard to tell exactly.
“And it’s something where you can use your knowledge and experience to see what might happen a little bit.
But it’s hard to know exactly because if you go from one domain to a different domain, it’s easy for our systems to say, take everything here and copy it here.
But if you go from a sub domain to a main domain, you’re basically merging different parts of the website.
And that final result that you have will depend on your final structure.”
Plan your subdomain migration ahead of time
Mueller then encouraged planning ahead by setting site migration from the old site to the new site on the main domain.
Mueller also suggested, in general, the value of mapping the old domain before a site migration in order to verify that the subdomain migration was successful.
In my opinion, it might be worth creating a map of the old subdomain’s structure using a crawling tool like Screaming Frog, generating the 301 redirects after the site has migrated, and then doing a full crawl of the old subdomain to make sure all the 301 redirects are there and to investigate which 404 page is on No response found signals a possible error.
Mueller continued with his answer:
“So, I think in general it’s something where you can make these kinds of changes.
But you have to watch that you do it in a reasonable way.
And what I would recommend here is to make sure you have a very clear mapping of your old site to the new one and then check all those old URLs.
You can use… there are many tools to test this.
But really make sure everything is moving properly.
Then check back by crawling the main domain again separately to make sure your new website structure is OK and that all pages can be found.
And for the most part, I suppose that will be fine.
I mean, it’s possible to make other mistakes too. But these are usually the most common type of problem.”
It is not clear how long the effects of migration will last
Each site is different in terms of theme, size, and how that theme fits into the overall website. John was understandably vague about how long it would take for the site migration process to stabilize things.
“I don’t know what to recommend in terms of how long it will take or what the final effect will be.
I think maybe you’ll see an effect for a few weeks until things settle down.
But it should be possible.
Site migration tips for Google News publishers
Mueller then shared advice that was specific to Google News publishers:
If you’re a Google News publisher, I’ll also make sure to contact anyone on Google News that’s right for you, in the Google News Publisher Help Center.
There is also a contact form, just to let them know that you are going from that set of URLs to a different set of URLs.
Sometimes they need to make some changes in publisher center… I don’t know all the details there.
But just kind of to make sure they are aware of this as well.
But in terms of the research itself, doing that step, making sure everything lines up, is basically what you need to do.”
Subdomain to migrate the main domain site
Making major changes to a website can be intimidating, especially when the site is currently doing so well. Something has to be broken to fix it, right?
Any changes driven by improvements should be in something less than it currently could be, like improving user experience, for example.
How to transfer the sub domain to the main domain
Watch at 45:05: