The following error occurs when starting an Oracle 11g RAC database. Only one of the nodes (rac01) can be started, and the other node cannot be started (rac02). This may be caused by a previous change to the cluster_database parameter. In Oracle RAC architecture this parameter must be set to TRUE.
When executing startup, the error message: ORA-01102: cannot mount database in EXCLUSIVE mode
Solution:
rac01 node:
SQL> show parameter cluster_database;
NAME TYPE VALUE
———————————— ———– ——————————
cluster_database boolean FALSE
cluster_database_instances integer 1
SQL> alter system set cluster_database=true scope=spfile;
System altered.
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup
ORACLE instance started.
Total System Global Area 1068937216 bytes
Fixed Size 2260088 bytes
Variable Size 734004104 bytes
Database Buffers 327155712 bytes
Redo Buffers 5517312 bytes
Database mounted.
Database opened.
SQL> select open_mode from v$database;
OPEN_MODE
——————–
READ WRITE
SQL> show parameter cluster_database;
NAME TYPE VALUE
———————————— ———– ——————————
cluster_database boolean TRUE
cluster_database_instances integer 2
SQL>
rac02 node:
[oracle@fanxin02 ~]$ sqlplus/as sysdba
SQL*Plus: Release 11.2.0.4.0 Production on Tue May 21 23:08:16 2019
Copyright (c) 1982, 2013, Oracle. All rights reserved.
Connected to an idle instance.
SQL> startup ORACLE instance started.
Total System Global Area 1068937216 bytes
Fixed Size 2260088 bytes
Variable Size 734004104 bytes
Database Buffers 327155712 bytes
Redo Buffers 5517312 bytes
Database mounted.
Database opened.
SQL> show parameter cluster_database;
NAME TYPE VALUE
———————————— ———– ——————————
cluster_database boolean TRUE
cluster_database_instances integer 2
SQL>
SQL> archive log list;
Database log mode Archive Mode
Automatic archival Enabled
Archive destination /u01/app/oracle/product/11.2.0.4/db_1/dbs/arch
Oldest online log sequence 12
Next log sequence to archive 13
Current log sequence 13
SQL>