I am administering a drupal 6 high traffic, high user base website and I would like to have it cloned into a development version in order to test modules before deploying on live.

I am unable to find anything related to this, no matter how hard I try.

What are the implications of cloning a live site into a test version on another server?

What aspects should I have in mind when doing this? e.g. avoid user notifications via email from test server

Thanks!