Standby Redo logs

Hi,

I have an Oracle12c database (non-RAC). I am trying to create a new Physical Standby database. On the Primary database, I have 3 redo groups with 3 members each and all members are 10 MB each. Redo group # are 1,2,3.

As per Oracle doc https://docs.oracle.com/database/121/SBYDB/create_ps.htm#SBYDB00200, (Step 3.1.3) I should create Standby Redo logs on the Primary database, using

SQL> ALTER DATABASE ADD STANDBY LOGFILE ('/oracle/dbs/slog1.rdo') SIZE 500M;
 
SQL> ALTER DATABASE ADD STANDBY LOGFILE ('/oracle/dbs/slog2.rdo') SIZE 500M;

I also read on the web that "In order to avoid any wait in reuse of standby redo logs, it is recommended that one more standby redo log group be retained than the number of online redo log groups configured on the primary database