While creating standby redo logfiles in standby database,we need to cancel the MRP recovery process in standby.
SQL> alter database add standby logfile group 4 '/u01/app/oracle/oradata/STD/onlinelog/std_redo1.log' size 100m;
alter database add standby logfile group 4 '/u01/app/oracle/oradata/STD/onlinelog/std_redo1.log' size 100m
*
ERROR at line 1:
ORA-01156: recovery or flashback in progress may need access to files
Cancel the MRP:
SQL> alter database recover managed standby database cancel;
Database altered.
Adding Standby logfiles,
SQL> alter database add standby logfile group 4 '/u01/app/oracle/oradata/STD/onlinelog/std_redo1.log' size 100m;
Database altered.