You’ll probably end up blocking Search Engines from crawling your site.
Also, checkout Restrict specific countries from accessing my Magento store
They’ll be in your apache logs. Look for a file with “ssl” and “access” in the name within /var/log/apache2. There are tools you can use to make reading these files easier, so you might wanna do some Google searches to find what they are.
As for tools and stuff to help you monitor/administer traffic and resources, you’d be better off asking one of the following forums (as this question mostly leans towards DevOps):