备机开启日志传输//(standby_logfile,standby_role)

alter system set log_archive_dest_2='service=xiandb valid_for=(standby_logfile,standby_role) db_unique_name=xiandb';
alter system set log_archive_dest_state_2='enable';

所有主机执行：

alter system set log_archive_config='dg_config=(ycloans,standbydb,xianzb,yunzhidb,zongbudb,xiandb)';

启动日志应用：

alter database recover managed standby database disconnect from session;

alter database recover managed standby database cancel;