Condition setup 1 big forum


I want setup 1 big forum for my company . forum very big using xenforo .

But xenforo not support model master , slaver .. So I have many server run database ,what is the moder run it ?

Or change not using mysql that using oracle is not ?

Or using moder NDB cluster is not ?

I see : forum with ~ 90 milion message . I dont know what how database or system design big load ....

Please comment , illustrated , described ....

Thank you /