--主库告警日志
Thu Mar 14 09:13:45 2019
Error 1017 received logging on to the standby
------------------------------------------------------------
Check that the primary and standby are using a password file
and remote_login_passwordfile is set to SHARED or EXCLUSIVE,
and that the SYS password is same in the password files.
returning error ORA-16191
Error 16191 for archive log file 3 to 'TO_standby'
Thu Mar 14 15:49:10 2019
Archived Log entry 203881 added for thread 2 sequence 59940 ID 0x53e28673 dest 1:
Errors in file /oracle/app/oracle/diag/rdbms/orcl/orcl2/trace/orcl2_nsa2_2753334.trc:
ORA-16191: Primary log shipping client not logged on standby
Thu Mar 14 15:49:10 2019
ARCb: Archival destination is a Primary RAC instance: 'TO_standby'
该问题十分严重，会导致备库同步进程抓取归档日志失败。但是，导致该问题的原因是主备库的sys密码文件不一致导致，可能是搭建过程中有人修改了sys密码，处理该问题的方法比较简单，从集群主库任意节点同步sys密码文件即可。
问题五
另外，在DG搭建过程中，可能遇到grid或者oracle通过lsnrctl查看监听状态的时候看到很多服务名，其中有很多l类似：
SYS$SYS.KUPC$C_1_20170318000713.ORCL，sys登陆sqlplus，show parameter service可以发现：
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
service_names string SYS$SYS.KUPC$C_1_20170318000713.orcl.US.ORACLE.COM,
SYS$SYS.KUPC$C_1_20170405000711.orcl.US.ORACLE.COM,
SYS$SYS.KUPC$S_1_20170314000710.ORCL,
SYS$SYS.KUPC$S_1_20170318000713.ORCL,
SYS$SYS.KUPC$S_1_20170323000707.ORCL,
SYS$SYS.KUPC$S_1_20170331000709.ORCL,
SYS$SYS.KUPC$S_1_20170403000701.ORCL,
SYS$SYS.KUPC$S_1_20170405000711.ORCL,
SYS$SYS.KUPC$C_1_20170314000710.ORCL......
导致该问题的原因是expdp或者impdp被异常终端导致，可以重置service_names或者重启数据库服务加以解决。