Oracle 10g: How to run two instances with the same database name in one ORACLE_HOME

If you cloned a database and need to run both instances with the same db_name from one $ORACLE_HOME i.e.:

 

*.db_name=TESTDB

use the following parameters in your pfile or spfile:

*.lock_name_space=ANOTHERDB
*.sp_name=ANOTHERDB

Where ANOTHERDB is the name of the cloned sid.

Note: this has been tested with Oracle 10.1 only