command to check if database vault is enabled the database
GO to $ORACLE_HOME/rdbms/lib and execute following:
ar -t libknlopt.a | grep -c kzvidv.o
If it gives output as 0, database vault is disabled and vice versa.
To Enable:
cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk dv_on
make -f ins_rdbms.mk ioracle
To Disable:
cd $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk dv_off
make -f ins_rdbms.mk ioracle