Re: Let BP run ONLY on subdomain
You can use this setting in wp-config.php
define ( ‘BP_ROOT_BLOG’, 3 ); <– 3 should be your blog id that you want it to run on.
define ( ‘BP_ENABLE_MULTIBLOG’, false ); <– this will prevent the bp functions from trying to attach to the theme of a blog that doens’t have a bp enabled blog
Here’s the codex link: