Convert / Migrate single Instance database to RAC database manually

Detailed steps to convert/migrate your single instance Oracle 12c Database to 2 node RAC database manually. The current environment is a single Instance Oracle 12c Database running on local storage. We would migrate it to shared storage with 2 RAC instances.

HIGH LEVEL STEPS:

• Preliminary Configuration and Verification
• Migrate the existing database to shared storage (Raw devices / ASM)
• Install the CRS Software
• Install Oracle RAC Software
• Configure Listeners, tnsnames files
• Modify/Create Initialization parameters, Password files
• Start the first Instance
• Create RAC data dictionary views
• Create Undo tablespace, Redo log files
• Bring up the Second RAC Instance
• Verify the status of RAC processes/Services

DETAILED STEPS of converting:

Pre-Setup:
———-

– Install the Oracle Clusterware and Oracle RAC Database software on nodes
– Copy/Edit the original init file as init$SID1.ora and init$SID2.ora
– Make sure SID, listeners, tnsnames, profile, password file are correct on both nodes

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Sample init, tnsnames, listener files

Moving DB to shared storage:

Create pfile from spfile on original instance, if using spfile
Shutdown original instance
Copy only datafiles on raw devices:

e.g.

dd if=/oradata/file_name of=/dev/raw/raw5

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Start instance in mount state:

startup mount;

Rename datafiles:
e.g.
alter database rename file '/u01/app/oracle/oradata/test12c/users01.dbf' to '/dev/raw/raw5';
alter database rename file '/u01/app/oracle/oradata/test12c/temp01.dbf' to '/dev/raw/raw6';

Alter database open;

ADD LOGFILES on shared storage:

(Don’t try to drop active group)

select group#, bytes, status from v$log;
select group#, member from v$logfile;

e.g.
alter database add logfile group 4 '/dev/raw/raw11' size 256M;
alter database add logfile group 5 '/dev/raw/raw12' size 256M;

select group#, status from v$log;
alter system switch logfile;

alter database drop logfile group 1;
alter database drop logfile group 2;
alter database drop logfile group 3;

select group#, bytes, status from v$log;

Alter database backup controlfile to trace;
shutdown immediate;

Edit init file and give raw location of controlfiles (rename spfile so Instance do not start using spfile)

startup mount;

Recreate controlfile;

Alter database open;

shutdown immediate;

Now Database has been moved to shared storage on original instance.

Now Start DB from RAC instance 1:
————————————-

(Make sure RAC instances have the latest init file)

START the first instance

Add tempfile

e.g.
ALTER TABLESPACE TEMP ADD TEMPFILE '/dev/raw/raw7'

Create RAC dictionary views:

@$ORACLE_HOME/rdbms/admin/catclust

shutdown immediate

From Linux prompt:
srvctl add database -d -o $ORACLE_HOME
srvctl add instance -d test12c -i test12c1 -n rac1
srvctl add instance -d test12c -i test12c2 -n rac2
srvctl start instance -d test12c -i test12c1

/ as sysdba

alter database add logfile thread 2 group 1 '/dev/raw/raw15' size 128M;
alter database add logfile thread 2 group 2 '/dev/raw/raw16' size 128M;
alter database enable thread 2;

create undo tablespace UNDOTBS2 datafile '/dev/raw/raw10' size 25M;

– Start second instance:

srvctl start instance -d test12c1 -i test12c2
——————————————-

Verify the RAC services:

crs_stat -t
srvctl status database -d test12c
srvctl stop database -d test12c
srvctl start database -d test12c
select instance_number instance#, instance_name, host_name, status from gv$instance;

You have now converted your single instance database to a 2 node RAC database.

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