多路复用 PRODCDB 数据库的所有日志组中的 redo log 文件，存放目录： /u01/app/oracle/oradata/MREDO
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;
