Hi Tom.
Would you elaborate a bit on what you mean by rebuild you middle tier? For example, are you needing to move the middle tier to a new server?
The SAS middle tier stores report content on the middle tier and some content in the Web Infrastructure Platform Database Server on your "compute" (SASApp) tier. Thus the answer to your question is going to depend on exactly what you mean and what you are trying to do.
We'll try to give you our persepctive if you can provide more detail.
thanks!
JAG