If you are in dilema of thinking that your domain has a crawl budget and in that crawl budget your subdomains are also included, then you are wrong.
Google allocates unique crawl budget to each of your domain and subdomains created.
This dilema has been busted recently when a user asked a question regarding crawl budget on LinkedIn. The user asked, Does the crawl budget of a domain A will get affected if it load a resource from domain B. Which means, does resource on domain B affect the crawl budget of domain A.
In response to this question, Google’s John Muller replied, the crawl budget of both the domains are independent.
The user who asked the question then further asked, Does it mean Google set the crawl budget by Hostname which means even within the same domain, several subdomains have their own crawl rate limits.
Gary Illyes (who is an Analyst at Google) confirmed the same.
So, it is now confirmed that Google set unique crawl budget for different hostnames.
