John Quinn writes about Scaling Drupal he is taking a one step at a time approach and is still writing his 4th and 5 stages.
His first step obviously is separating the drupal from a separate database server, and he chooses mysql for this purpose, moving your DB to a different machine is a good thing to do.
However then he gets this crazy idea of using NFS to share his his drupal shared files :(
(he even dares to mention that the setup ease is good) Folks, we abandonned NFS in the late nineties. NFS is still a recipe for disaster, it has performance issues , it as stability issues (stale locks), and no security admin in his right mind will tolerate portmap to be running in his DMZ.
(Also think about