Regarding application sharing in win2k

hello all,
I am having win2k network with two win2k domain controller server.Now day company ask me to install one medical application .Its a
server/client application I have implemented this software on both domain controller and client Pc ,now compny ask me to do replication between this two DC for the data of that application so that if one DC fail The application can run on other DC and the same data also be accesible.so plz tell me what should I do