Oracle: Modifying MAXDATAFILES after database creation

MAXDATAFILES controls how many data files you can have in your database. It is set during the create database command. In order to change it, you have to update the control files which is obviously not something you want to do on a regular basis. To update the MAXDATAFILES parameter, do the following:

1. With the database open, enter svrmgrl and execute the following:
   
   alter database backup controlfile to trace;
   
   The preceding command generates a trace file in the user dump file destination directory. This trace will contain a create controlfile command.
   
   
2. Shutdown the database.
   
   
3. Edit the trace file, removing any header information and leaving the create controlfile command. Update the MAXDATAFILES parameter within the create controlfile command. Save that information to a different filename.
   
   
4. Backup the existing control files; they'll be used if the feces hits the rotary ventrilator.
   
   
5. Mount the database in exclusive mode
   
   startup mount ${SID} exclusive
   
   
6. Run the create controlfile script that you generated above.
   
   
7. Open the database.
   
   alter database open
   
   
8. Once the database is opened successfully, you can remove the old control files.