The DBNEWID utility has the following restrictions:
To change the DBID of a database, the database must be mounted and must have been shut down consistently before mounting. In the case of an Oracle Real Application Clusters database, the database must be mounted in NOPARALLEL mode.
You must open the database with the RESETLOGS option after changing the DBID. However, you do not have to open with the RESETLOGS option after changing only the database name.
No other process should be running against the database when DBNEWID is executing. If another session shuts down and starts the database, then DBNEWID terminates unsuccessfully.
All online data files should be consistent without needing recovery.
Normal offline data files should be accessible and writable. If this is not the case, then you must drop these files before invoking the DBNEWID utility.
All read-only tablespaces must be accessible and made writable at the operating system level before invoking DBNEWID. If these tablespaces cannot be made writable (for example, they are on a CD-ROM), then you must unplug the tablespaces using the transportable tablespace feature and then plug them back in the database before invoking the DBNEWID utility.
The DBNEWID utility does not change global database names. See "Considerations for Global Database Names".