About to have a patio poured (concrete) and want to build a "cover" over it. Basically a 20x20, 6 posts (3 down each side). I'm going to use 8x8's for the posts and go back and rock around the bottoms of the posts for decoration. I understand I'm not supposed to put the posts into the ground in concrete. I understand I need to pour "pillars" and use post anchors. My question is, and what I can't wrap my head around, if it's just a "pavilion" type structure meaning no walls, just posts, what keeps the thing from "racking" once it's built?