1、RAC数据库调整为归档模式步骤：
SQL> alter system set cluster_database=false scope=spfile sid='orcl1';
SQL> alter system set db_recovery_file_dest='+ORAFLASH' scope=spfile;
SQL> alter system set db_recovery_file_dest_size=20g scope=spfile;
$ srvctl stop database -d orcl
$ sqlplus / as sysdba;
SQL> startup mount;
SQL> alter database archivelog;
SQL> alter system set cluster_database=true scope=spfile sid='orcl1';
SQL> shutdown immediate;
$ srvctl start database -d orcl
SQL> select name,log_mode,flashback_on from v$database;

2、RAC数据库启动闪回特性步骤：
确认数据已经运行在归档模式中：
SQL> archive log list;
SQL> alter system set cluster_database=false scope=spfile sid='orcl1';
SQL> alter system set db_recovery_file_dest='+ORAFLASH' scope=spfile;
SQL> alter system set db_recovery_file_dest_size=20g scope=spfile;
$ srvctl stop database -d orcl
SQL> startup mount;
SQL> alter database flashback on;
SQL> alter system set cluster_database=true scope=spfile sid='orcl1';
SQL> shutdown immediate;
$ srvctl start database -d orcl
注意：可以根据需要为特定的表空间打开或关闭闪回：
SQL> alter tablespace users flashback on;
SQL> alter tablespace users flashback off;

SQL> select name,log_mode,flashback_on from v$database;