We have build up our DR environment recently.
We have 2 identical, clustered environments and network based storage.
The Storage and the DB (Oracle Dataguard) are permanently replicated from the main environment to the fail-over environment.
For the case that the main environment will be unavailable, the fail-over environment starts the services and instances based on the latest replicated storage data and DB data using the same logical IP-Adresses and DNS-Aliases as the original environment.
Regards,
Holger