Adding online redo log groups

We use the ADD LOGFILE GROUP  SQL statement  to add more log groups to our existing oracle database.

SQL >  ALTER DATABASE ADD LOGFILE GROUP <number>  (‘path of logfile1′,’path of logfile2’,’3’…)  SIZE <>;

Example:

SQL> conn sys/orcl@to_primary as sysdba
Connected.

---- Create log group with two redo log members
SQL> alter database add logfile group 8
  2  ('D:\app\Admin\virtual\oradata\orcl\redoa8.log',
  3  'D:\app\Admin\virtual\oradata\orcl\redob8.log') SIZE 50M;
 Database altered.
 SQL>

NOTE: It is recommended that the log files to be created should have the same size with the already created log files.