一个DG环境的ORA16047:DGIDmismatchbetweendestinationsettingandtargetdatabase问题排查及监听VNCR特性

DG环境的现在已经是一个基础常见的架构&＃xff0c;整体架构成熟稳定&＃xff0c;已经是公司的常规实施项目。近期&＃xff0c;同事转来一个问题&＃xff0c;DG搭建好后&＃xff0c;报错ORA-16047: DGID mismatch between destination setting and target database。 这个报错看起来是DGID不匹配&＃xff0c;通常配置log_archive_config&＃61;&＃39;DG_CONFIG参数即可&＃xff1b;本次问题排查发现&＃xff0c;此参数设置正常&＃xff0c;为何仍有此问题&＃xff1f;

接下来基于DG的配置原理出发&＃xff0c;一步步排查此问题&＃xff1a;

1.根据报错&＃xff0c;查看log_archive_config&＃61;&＃39;DG_CONFIG参数&＃xff0c;检查主、备节点的DB_UNIQUE_NAME&＃xff1b;配置正常。

2.上一步排查没发现问题&＃xff1b;此时基于DG的传输原理&＃xff0c;是基于DG的传输参数如 log_archive_dest_2中的值来指定的&＃xff1b;那么来分析此参数的值&＃xff0c;本次为SERVICE&＃61;HZDBRAC LGWR ASYNC VALID_FOR&＃61;(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME&＃61;HZDBRAC&＃39;

3.对于 log_archive_dest_2参数&＃xff0c;SERVICE&＃61;HZDBRAC通过tnsnames.ora指定了备机的信息&＃xff08;IP、端口、SERVICE_NAME&＃xff09;&＃xff0c;以及DB_UNIQUE_NAME。在主节点检查&＃xff0c;格式无误。

4.检查备机配置&＃xff0c;查看监听配置时&＃xff0c;发现异常&＃xff1a;RAC到单机环境&＃xff0c;监听程序的serviceK出现三个数据库实例&＃xff1b;

[grid&＃64;rac11g02 ~]$ lsnrctl status listener_scan1LSNRCTL for Linux: Version 11.2.0.4.0 - Production on 24-FEB-2022 14:44:45Copyright (c) 1991, 2013, Oracle. All rights reserved.Connecting to (DESCRIPTION&＃61;(ADDRESS&＃61;(PROTOCOL&＃61;IPC)(KEY&＃61;LISTENER_SCAN1)))
STATUS of the LISTENER
------------------------
Alias LISTENER_SCAN1
Version TNSLSNR for Linux: Version 11.2.0.4.0 - Production
Start Date 23-FEB-2022 12:19:12
Uptime 1 days 2 hr. 25 min. 32 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /u01/11.2.0/grid/network/admin/listener.ora
Listener Log File /u01/11.2.0/grid/log/diag/tnslsnr/rac11g02/listener_scan1/alert/log.xml
Listening Endpoints Summary...(DESCRIPTION&＃61;(ADDRESS&＃61;(PROTOCOL&＃61;ipc)(KEY&＃61;LISTENER_SCAN1)))(DESCRIPTION&＃61;(ADDRESS&＃61;(PROTOCOL&＃61;tcp)(HOST&＃61;192.168.3.105)(PORT&＃61;1521)))
Services Summary...
Service "HZDB" has 3 instance(s).Instance "HZDB", status READY, has 1 handler(s) for this service... &＃61;&＃61;&＃61;>>>RAC到单机环境&＃xff0c;出现三个数据库实例&＃xff1f;Instance "HZDB1", status READY, has 1 handler(s) for this service...Instance "HZDB2", status READY, has 1 handler(s) for this service...

5.问题总结&＃xff1a;检查监听日志&＃xff0c;可以发现是备机&＃xff0c;在搭建时使用RAC的参数修改时未删除remote_listener参数&＃xff0c;导致备机的实例也注册到了RAC环境&＃xff0c;并且排在SERVICE的第1个&＃xff1b;这样单机在切换为主节点&＃xff0c;向RAC(备节点&＃xff09;传输数据时&＃xff0c;就会出现表面上看最终要连&＃xff1a;log_archive_dest_2的SERVICE&＃61;HZDBRAC连的是RAC&＃xff0c;实际又绕回连接本机。所以出现ORA-16047: DGID mismatch between destination setting and target database不匹配报错。

在单机上修改参数alter system set remote_listener&＃61;&＃39;&＃39;;后&＃xff0c;重新ENABLE日志传输参数后&＃xff0c;恢复正常。这也说明监听的VNCR特性还是有必要设置的&＃xff0c;不然可能会被误操作攻击影响正常业务&＃xff01;&＃xff01;