问题(一)
在主备库（rac+single standby）搭建完成后，发现主库一个节点和备库的错误信息如下：
主库问题

ERROR_CODE SEVERITY      MESSAGE                                                                          TIMESTAMP
---------- ------------- -------------------------------------------------------------------------------- --------------------
     16191 Error         PING[ARC1]: Heartbeat failed to connect to standby 'racdb_st'. Error is 16191.   04-APR-13 20:54:28
      1017 Error         Error 1017 received logging on to the standby                                    04-APR-13 20:55:59
     16191 Error         PING[ARC1]: Heartbeat failed to connect to standby 'racdb_st'. Error is 16191.   04-APR-13 20:55:59
      1017 Error         Error 1017 received logging on to the standby                                    04-APR-13 20:57:30
     16191 Error         PING[ARC1]: Heartbeat failed to connect to standby 'racdb_st'. Error is 16191.   04-APR-13 20:57:30
      1017 Error         Error 1017 received logging on to the standby                                    04-APR-13 20:59:01
     16191 Error         PING[ARC1]: Heartbeat failed to connect to standby 'racdb_st'. Error is 16191.   04-APR-13 20:59:01
      1017 Error         Error 1017 received logging on to the standby                                    04-APR-13 21:00:31
     16191 Error         PING[ARC1]: Heartbeat failed to connect to standby 'racdb_st'. Error is 16191.   04-APR-13 21:00:31

备库问题

ERROR_CODE SEVERITY      MESSAGE                                                                          TIMESTAMP
---------- ------------- -------------------------------------------------------------------------------- --------------------
      1017 Error         Error 1017 received logging on to the standby                                    04-APR-13 20:48:46
     16191 Error         FAL[client, MRP0]: Error 16191 connecting to racdb_1 for fetching gap sequence   04-APR-13 20:48:46
      1017 Error         Error 1017 received logging on to the standby                                    04-APR-13 20:48:57
     16191 Error         FAL[client, MRP0]: Error 16191 connecting to racdb_1 for fetching gap sequence   04-APR-13 20:48:57
      1017 Error         Error 1017 received logging on to the standby                                    04-APR-13 20:49:09
     16191 Error         FAL[client, MRP0]: Error 16191 connecting to racdb_1 for fetching gap sequence   04-APR-13 20:49:09
      1017 Error         Error 1017 received logging on to the standby                                    04-APR-13 20:49:20
     16191 Error         FAL[client, MRP0]: Error 16191 connecting to racdb_1 for fetching gap sequence   04-APR-13 20:49:20

问题原因：
1、密码文件不一致，需要将密码文件进行复制（11g）
2、db_unique_name设置的问题

问题（二）
主备可以正常同步，但是主备库切换后，新主库问题的alert日志中报错如下：

<msg time='2013-04-05T00:32:42.693+08:00' org_id='oracle' comp_id='rdbms'
 client_id='' type='UNKNOWN' level='16'
 host_id='OELx64' host_addr='192.168.137.146' module=''
 pid='3226'>
 <txt>Errors in file /u01/app/oracle/diag/rdbms/racdb_st/racdb_st/trace/racdb_st_cjq0_3226.trc:
ORA-00604: error occurred at recursive SQL level 1
ORA-06544: PL/SQL: internal error, arguments: [56327], [], [], [], [], [], [], []
ORA-06553: PLS-801: internal error [56327]
 </txt>
</msg>

问题原因：
查看MOS：ID 1436552.1后，说是版本位数不一致导致的。
经查，这个rac+single standby的DG确实是在不同的版本位数下实施的。
主库：

[oracle@11grac1 ~]$ getconf LONG_BIT
32

备库：

[root@OELx64 ~]# getconf LONG_BIT
64