Hi,
I accept that this is not proper setup having all servers in one data center, But as of now we have this setup only as per our management decision, So let's keep this concern aside (May be in near future this will be handled properly).
We have setup this using Oracle data guard, So tnsnames & listener files are maintained for both primary & DR host. Also environment variables exist on both primary & DR host with the respective host details as require. We can do tnsping from primary & DR host, So no issue with that, Even SWITCHOVER went smoothly. The only issue we have is, SAP can not connect to DR database after SWITCHOVER. We are now suspecting on tnsnames.ora file which is on SAP application host ( f:\usr\sap\JE2\SYS\profile\oracle\tnsnames.ora)
Kindly let me know if you have any other suggestion.
Regards,
kiraang.