The design

After a lot of suggestions we came up with the following design (fig.2):
       Fig.2
         

As you can see, we removed one of the routers we intended to use (we decided there is no need for a more complicated design). And instead of SAN (as we intended) we are now using NAS (Network-attached storage).

   * here we ought to thank our teacher for clearing this (the NAS thingy) to us, so ->

THANK YOU!