Migrating a site to a new domain may affect its position in search results and number of indexed pages. These changes can be minimized if the robot recognizes the new domain as the main mirror of the old domain. To tell the robot about the new address, use the Migrate site tool in the beta version of the Yandex.Webmaster service.
Before beginning the migration, make sure that:
You have access to manage both domains and their configurations.
The robots.txt files allow the Yandex robot to index both domains. The robots.txt files must have the same content so the robot can use the same addresses for checking mirrors. You can use the robots.txt analysis tool to analyze the robots.txt files.
There are two ways to define the address of the main mirror:
Set the Host directive in the robots.txt files for all the mirrors, provided that the content is identical on all the sites. In particular, use the Host directive if you specified a new domain as an alias of an existing domain in your hosting control panel.
Note that any Cyrillic domain names must use Punycode format in robots.txt files.
Set a permanent server redirect with the HTTP code 301. When using the redirect, follow these recommendations:
When it gets a redirect, the robot indexes only the redirect target. So you should only use a redirect if you don't need the site on the old domain to participate in search.
If possible, configure a redirect for each page on the old site to the corresponding page on the new site. If the content or structure of the mirrored sites differs, configure redirects according to the redirect rules.
We don't recommend redirecting users from every page on the old site to the main page on the new one. This way of organizing redirects won't interfere with grouping mirrors, but it's inconvenient for users and slows down how the Yandex robot indexes the new site.
To group mirrors, the Yandex robot only needs Host directives in the robots.txt files on all the mirrors. You don't need to configure a redirect.
Make sure that all your methods of grouping mirrors (both redirects and Host directives for each mirror) are pointing to the same main mirror for the site. Otherwise, the robot might choose the wrong domain as the main mirror.
It usually takes about a month to group mirrors, regardless of which way you choose to set the main mirror.