Today when i was trying to create a datafile i got this error :
ORA-00059: maximum number of DB_FILES exceeded
The parameter DB_FILES by default has the value of 200 datafiles. My RAC database was created with the maxdatafiles parameter 1024 so i had to modified the db_files parameter.
You need to have the same value in all instances of rac database and you muste restart the database after this change.
alter system set db_files=[VALUE] scope=spfile sid='*';
To set the parameter to the specified value.