1.创建目录

mkdir -p /u01/app/oracle/oradata/MREDO

2.查看日志文件路径

select group#,member from v$logfile;

3.增加日志组文件

alter database add logfile member '/u01/app/oracle/oradata/MREDO/redo01.log'
to group 1;
alter database add logfile member '/u01/app/oracle/oradata/MREDO/redo02.log'
to group 2;
alter database add logfile member '/u01/app/oracle/oradata/MREDO/redo03.log'
to group 3;

4.查看日志文件

select group#,member from v$logfile;