We have an enterprise web app to which our clients post/upload lots of documents [mainly images and pdf files] via web interface, iphone app etc etc. We are also using imagick to split pdf documents into images.
Also, large number of mysql SELECT/UPDATE/DELETE queries happen all day.
Currently, all of this is happening on same server and we are planning to split the process in 3 stages :
1) a server only for database
2) a server only for documents (document upload, splitting etc)
3) a server for the main php web app
Is there any drawback with this kind of structure as compared to hosting everything on same server ?