在做迁移时，由于某种原因导致回退，现在准备将备库的数据库删除，然后重新部署dg，但在删除备库的时候遇到一些小问题，以下的操作是在节点一执行
[oracle@sde1 ~]$ sqlplus / as sysdba SQL*Plus: Release 11.2.0.3.0 Production on Wed Aug 15 10:46:44 2018 Copyright (c) 1982, 2011, Oracle. All rights reserved. Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP, Data Mining and Real Application Testing options SQL> SQL> SQL> drop database; drop database * ERROR at line 1: ORA-01586: database must be mounted EXCLUSIVE and not open for this operation
提示执行该命令数据库必须处于mount状态(EXCLUSIVE模式mount)，关库以RESTRICTED模式开启
SQL> shutdown immediate; Database closed. Database dismounted. ORACLE instance shut down. SQL> SQL> startup mount exclusive restrict; ORACLE instance started. Total System Global Area 4.1557E+10 bytes Fixed Size 2237328 bytes Variable Size 1.3959E+10 bytes Database Buffers 2.7515E+10 bytes Redo Buffers 81035264 bytes Database mounted. SQL> show parameter instance; NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ active_instance_count integer cluster_database_instances integer 2 instance_groups string instance_name string sde1 instance_number integer 1 instance_type string RDBMS open_links_per_instance integer 50 parallel_instance_group string parallel_server_instances integer 2 SQL> SQL> alter system enable restricted session; System altered. SQL> SQL> drop database; drop database * ERROR at line 1: ORA-01586: database must be mounted EXCLUSIVE and not open for this operation
还是报错，明明是以exclusive模式mount的数据库实例，怎么还会报这个错误呢？看一下alert日志看会不会有发现：
ALTER DATABASE MOUNT Successful mount of redo thread 2, with mount id 3008285745 Database mounted in Shared Mode (CLUSTER_DATABASE=TRUE) Lost write protection disabled Completed: ALTER DATABASE MOUN
通过alert日志我们可以清楚的看到，虽然我们在mount的时候指定了exclusive,但是因为CLUSTER_DATABASE=TRUE，所以数据库还是会以Shared模式被mount mos中有一篇note提到如果是RAC数据库使用DROP DATABASE 要将设置CLUSTER_DATABASE=FALSE(alter system set cluster_database=FALSE scope=spfile;)，然后mount数据库，再删除 可以参考What Is The Best Way To Remove A Database If Using Oracle 10.x And Higher (Doc ID 362047.1)
SQL> show parameter luster NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ cluster_database boolean TRUE cluster_database_instances integer 2 cluster_interconnects string SQL> alter system set cluster_database=false scope=spfile; System altered. SQL> shutdown abort ORACLE instance shut down. SQL> SQL> startup mount exclusive restrict; ORACLE instance started. Total System Global Area 4.1557E+10 bytes Fixed Size 2237328 bytes Variable Size 1.3959E+10 bytes Database Buffers 2.7515E+10 bytes Redo Buffers 81035264 bytes Database mounted. SQL> SQL> alter system enable restricted session; System altered. SQL> SQL> drop database; Database dropped. Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP, Data Mining and Real Application Testing options SQL>
若还有残留文件，进入asm目录手动删除。
