Q- What is the difference in mirror site and sub domain?

[denniemark]

“You have to be very careful when using Sub Domains because if the content on your sub Domain is too close to the main site, and since search engines look at sub Domains as separate sites, it will degrade your rank because it will consider this as multiple sites with the same content.”

If my site has lots of sub domain, then Google can be banned my site and effect on my site ranking?

[Nile Hadwards]

As of me Mirror site and sub-domain are completely different in nature. Where mirror site contain duplicate content of main website and can ban your website. On the other hand subdomain has no illegal things like that.

[elmerkit]

Mirror is just another access point while sub domain is a part of a website.