NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
db_files integer 200
SQL> alter system set db_files=1000 scope=spfile sid='*';
Total System Global Area 3640654056 bytes
Fixed Size 8902888 bytes
Variable Size 855638016 bytes
Database Buffers 2768240640 bytes
Redo Buffers 7872512 bytes
ORA-01105: mount is incompatible with mounts by other instances
ORA-01174: DB_FILES is 1000 buts needs to be 200 to be compatible