What will be the reaction of search engines to mirrors with different content?

Question

Domain name market

There is a main domain:
www.site.ru it has an exact copy of the site.ru
type - a standard mirror with the same content as on the main domain.
But there are other mirrors (configured as mirrors on the hoster's side):
www.site1.ru, www.site2.ru ... www.siteN.ru - the number is not limited.
- each of the sites works as a mirror of www.site.ru, but displays different content.
Question: can there be problems with the indexing of each site?

Answer 1

And why is such a "strange" support of the site needed at all?
most of the general texts from different "copies" will go to the end of the search results