Starting a database on a replica server We had a oracle database instance on a server A. We created a replica of server A named B. Where all the files, directory structure and  environment variables were replicated on server B. I wanted to ask if I can directly start the database on the replica server or I need to do some pre-requistes to start the database on the replica server B.
There should be no problem to start the database. There are however some things to consider:


The databases have both the same name, unique name, and DBID. This can cause problems if you want to back them both up by RMAN.
The configuration of sqlnet will have the name server A. Therefore the database might not be accessible from another server.


So change the DBID and unique name (Check the documentation on these subjects) and check the configuration files of sqlnet (normally in the $ORACLE_HOME/network/admin directory) for references to server A.