The folks over at vbulletin were not able to answer this, figured one of the largest forums online may. vBulletin lets you load balance mysql on the backend but what gets load balance? Ever request contains a write but you only want to load balance the reads. I guess all and all, what's the best way to load balance vbulletin and mysql. Don't want mysql replication
Actually if the server load gets high then some of the modifications would be temporary disabled for normal users till server attains stability .