DBCA Not Listing Existing Single Instance DB When Trying To Convert it to RAC [ID 359356.1]

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Modified 25-AUG-2011 Type PROBLEM Status PUBLISHED

In this Document
Symptoms
Changes
Cause
Solution
Scalability RAC Community

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Applies to:
Oracle Server - Enterprise Edition - Version: 10.1.0.2 to 10.2.0.4 - Release: 10.1 to 10.2
Information in this document applies to any platform.

Symptoms
Trying to convert a single instance DB to RAC by using dbca to add 2nd instance on 2nd node, DBCA does not list the single instance DB in the DB list. But if select 'Oracle single instance database' instead of 'Oracle RAC database' on the first screen of dbca, the single instance is listed there.

Changes
New setup.
Cause
For single instance, dbca read database information from /etc/oratab, but for RAC database, dbca retrieves database information from OCR.
The database is not listed because it is not registered in OCR.

Solution
To convert a single instance to RAC instance, it is best to use rconfig utility. Please refer Note.387046.1 RCONFIG Frequently Asked Questions.

If you really want to use dbca to achieve this, please execute the following steps:

1. Change SID to have suffix number 1. In following example, we will use single instance SID as ORCL. So set RAC instance SID on node 1 to be:
export ORACLE_SID=ORCL1
2. Create init parameter file for new SID, eg:
$ORACLE_HOME/dbs/initORCL1.ora
It either has all parameters or has spfile defined to point to a shared location for spfile.

3. Make sure the signle instance has all cluster database parameters set, eg:
*.cluster_data=true
*.cluster_database_instances=2
ORCL1.thread=1
ORCL1.instance_number=1
ORCL1.undo_tablespace='UNDOTBS1'
4. Instance ORCL1 on node 1 is started with cluster_database =true.

5. On ORCL1, create cluster dictionary:
sqlplus / as sysdba
sql> @?/rdbms/admin/catclust.sql
6. Take backup of current OCR if needed:
$ORA_CRS_HOME/bin/ocrconfig -showbackupThis should show several OCR backup taken automatically.
If you want to take another one:
As root:
$ORA_CRS_HOME/bin/ocrconfig -export /tmp/ocr.backupThis file can be used via $ORA_CRS_HOME/bin/ocrconfig -import if restore is needed.

7. Register database (instance) information into OCR via srvctl
srvctl add database -d -o
srvctl add instance -d -i -n

eg:
srvctl add database -d ORCL -o /u01/apps/oracle/product/db_1
srvctl add instance -d ORCL -i ORCL1 -n RACHOST1

8. restart database using srvctl and make sure it works as expected
srvctl stop instance -d ORCL -i ORCL1
srvctl start instance -d ORCL -i ORCL1

9. Launch dbca again, now you should see this database information, proceed with add instance steps.

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?Oracle Database Products > Oracle Database > Oracle Database > Oracle Server - Enterprise Edition
Keywords
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DBCA; OCR; RCONFIG; SPFILE

查詢rconfig的時候記錄了手工遷移的步驟

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