Mirror sites are copies of websites that are hosted on a different server. They’re used by websites that seek to distribute their traffic between different web servers, optimising server location for each visitor so that global users experience lower latency.
A mirror website can feature the exact same URL as the original site, a different subdomain, or even a different domain name entirely. Importantly, if the URL of a mirror site is not identical to the original site, canonical tags should be used in order to avoid Google picking up on duplicate content as a reason to demote the website.
