I have 3 websites with same design and same content in one server. This is problem in seo perceptive?
google will consider 2 of them having duplicate content and remove them from indexing. if you are lucky, you will keep one site only and if not, google may end up deindexing all 3 of them. having multiple sites on same server is OK but they must have unique content.
Start with site 2 and gradually change content and then with Site 3. You don't want exact content on different sites even if they are on disparate servers. Duplicate content penalty is real. Some guy stole my site and used my content and i was penalized. You don't have to change 100% of the content just 20% would do. Rewrite the same article in a different way by moving paragraphs around and add more content to that article.