Database compatible parameter is set to "11.2.0.0.0" and diskgroup database compatibility attribute is set to "11.2.0.2.0".

Issue:

Database compatible parameter is set to “11.2.0.0.0” and diskgroup database compatibility attribute is set to “11.2.0.2.0” while creating new database.
Solution
$ cd $ORACLE_HOME/assistants/dbca/templates/
[oracle@db01 templates]$ ls -lha
total 286M
drwxr-xr-x 2 oracle oinstall 4.0K Oct  5 19:03 .
drwxr-xr-x 6 oracle oinstall 4.0K Jun 30 13:01 ..
-rw-r--r-- 1 oracle oinstall 5.0K Oct  5 19:03 Data_Warehouse.dbc
-rw-r--r-- 1 oracle oinstall 5.0K Oct  5 18:56 Data_Warehouse.dbc.bk
-rwxr-xr-x 1 oracle oinstall  21M Sep 22  2011 example01.dfb
-rwxr-xr-x 1 oracle oinstall 1.5M Sep 22  2011 example.dmp
-rw-r--r-- 1 oracle oinstall 4.9K Sep 17  2011 General_Purpose.dbc
-rw-r--r-- 1 oracle oinstall  12K Feb 15  2010 New_Database.dbt
-rwxr-xr-x 1 oracle oinstall 9.3M Sep 22  2011 Seed_Database.ctl
-rwxr-xr-x 1 oracle oinstall 254M Sep 22  2011 Seed_Database.dfb
Edit template
Find
   <InitParamAttributes>
      <InitParams>
         <initParam name="db_name" value=""/>
         <initParam name="dispatchers" value="(PROTOCOL=TCP) (SERVICE={SID}XDB)"/>
         <initParam name="audit_file_dest" value="{ORACLE_BASE}/admin/{DB_UNIQUE_NAME}/adump"/>

Enable DDL Audit

ALTER SYSTEM SET enable_ddl_logging=TRUE
The result will go to
$ORACLE_BASE/diag/rdbms/db1/DB1/alert
log.xml

ORA-1113 when open database

Issue:
alter database open
ORA-1113 signalled during: alter database open...
Starting ORACLE instance (normal)
Solution:
startup mount
ALTER DATABASE RECOVER  database;
or
Check backup mode
        -- Hot backup status
        SELECT  COUNT(*) FROM v$backup WHERE status ='ACTIVE';
        -- Tablespaces in hot backup mode
        SELECT  distinct ddf.tablespace_name tablespace_name
        FROM    v$backup vb, DBA_DATA_FILES ddf
        WHERE   vb.status ='ACTIVE' and vb.file#  = ddf.file_id;
ALTER TABLESPACE (<tbs_name from the query before>) END BACKUP ;

Agent is Running but Not Ready

Issue
[oracle@db1 bin]$ ./emctl status agent
Oracle Enterprise Manager 11g Release 1 Grid Control 11.1.0.1.0
Copyright (c) 1996, 2010 Oracle Corporation.  All rights reserved.
---------------------------------------------------------------
Agent Version     : 11.1.0.1.0
OMS Version       : 11.1.0.1.0
Protocol Version  : 11.1.0.0.0
Agent Home        : /u01/app/oracle/product/EMbase/oracle/MW/agent11g/db1.local
Agent binaries    : /u01/app/oracle/product/EMbase/oracle/MW/agent11g
Agent Process ID  : 24910
Parent Process ID : 24865
---------------------------------------------------------------
Agent is Running but Not Ready
Workout
1. emctl stop agent
2. ps -ef | grep emagent
        kill all the process
3. emctl start agent
        Oracle Enterprise Manager 11g Release 1 Grid Control 11.1.0.1.0
        Copyright (c) 1996, 2010 Oracle Corporation.  All rights reserved.
        Starting agent ........................................................................................................................... started but not ready.
Solution
emctl unsecure agent
emctl secure agent

How to convert to cluster database

Convert to cluster DB, make database clustered
1. copy init<>.ora and orapwd<> to another host
2. save spfile to init<>.ora
3. create UNDOTBS2,..
4. add logfiles for thread 2,..
5. assign UNDOTBS for each instance
6. assign instance_number for each instance;