Converting a Single Instance DB into a RAC DB (Oracle Exadata) Gotchas

Posted: July 19, 2017 in Database Administration, High Availability, RAC

Good afternoon, Oracle Pioneers!

A few months ago (maybe a year ago), I published an article on how to convert a single instance database into a RAC database.  Converting a Single Instance To RAC DB However, that article assumed this was already a RAC database at some prior to its migration and subsequent (RACifying) **Yes RACifying is a word I made up or stole from someone**

If this database is and has always been a single instance, there are likely a few missing parameters that are needed in order to make it into a multiple instance database.

So here is my updated version of how to convert a single instance database into a RAC Database using command line and srvctl. These steps will work for 11g or 12c databases.

After single instance is available do this:
If this is a single instance you are migrating and “racifying”, you must create undotbs2 and logfiles for thread 2 to match number and size of thread 1.

  1. SQL> create undo tablespace undotbs2 datafile ‘+DATA’ size 4G;
  2. SQL> alter database add logfile thread 2 group 5 size 4096M;   
  3. SQL> alter database enable public thread 2; 
  4. Verify these parameters are set in your pfile:

control_files **Update location info from +data and +reco Location         

db_name1.thread=1                                                                                                                                 db_name2.thread=2                                                                                                           db_name1.undo_tablespace=’UNDOTBS1′                                                                 db_name2.undo_tablespace=’UNDOTBS2′                                                                   db_name1.local_listener='(ADDRESS=(PROTOCOL=TCP)(HOST=xdt*client01-vip)(PORT=9653))’ db_name2.local_listener='(ADDRESS=(PROTOCOL=TCP)(HOST=xdt*client02-vip)(PORT=9653))’ db_name1.instance_number=1 db_name2.instance_number=2 *.remote_listener=’xdt*-scan:9653’5.

5. edit $ORACLE_HOME/dbs/init<db_name>.ora to a one line file reading location of new spfile:

6. copy file to $ORACLE_HOME/dbs/init<db_name><inst#>.ora on all nodes

7.   shutdown immediate;

8. Create srvctl setup. See my previous article on converting a single instance to a RAC DB.

9. Log into instance and set cluster database to true:

srvctl start instance -d db_name -i db_name1

SQL> alter system set cluster_database=true scope=spfile sid=’*’;

10. Shutdown and restart database with srvctl:

srvctl stop database -d db_name -o immediate -f

srvctl start database -d db_name

Good luck and let me know if you have any issues! Keep on RACifying out there!


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