set ORACLE_SID=EKP

sqlplus /nolog

conn / as sysdba

SQL> archive log list;

show parameter db_reco
show parameter log_archive

alter system set db_recovery_file_size=20G;

SQL> shutown immediate

SQL> conn / as sysdba

SQL> startup mount

SQL> alter database archivelog; 启动归档

SQL> alter database open;

SQL> archive log list;

改变为20G

SQL〉alter system switch logfile;

show all;

configure controlfile autobackup on; 启动控制文件自动备份
configure retention policy to redundancy 4; 备份策略，4个版本

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