How to cluster a hub server

Hello Guys!

Your help could be useful and greatful.

Well, I was wandering how to put my hub server in a cluster for failover it with an another server.

The topology Hub to spoke:

1 Hub (serverA):administration server which is connected to Internet for SMTP inbound/outbound transfer mails.

4 spokes (server B, C, D, E): These servers are connected to the server with connection documents. They can send mail to Internet across serverA.

Server A has got domain Foreign domain document and Foreign SMTP document, global.

I have already add a server A’ which is the failover server of the server A. Both are CLUSTERED.

Question:

How should I configure the serverA’? Should I copy the exact parameters from serverA to server A’? I mean parameters of server document, configuration document?

Thank so much.