Can you downgrade your Oracle Restart installation from Oracle 12c back to Oracle 11g?
Actually there’s no real direct downgrade supported for Oracle Restart. But of course there’s a way to do it.
Basically it is:
- Deconfigure Oracle Restart in 12c
- Configure Oracle Restart in 11g
But wait a minute. It is very important to know if you have upgraded your database already. If that is the case then first you MUST downgrade your database(s) as you can’t manage a higher version Oracle Database with a lower version Clusterware.
So first of all, please downgrade your Oracle database(s) first:
- Downgrade your database – if you haven’t changed COMPATIBLE during the upgrade!
At the next stage you’ll need to “downgrade” the Oracle Clusterware resp Grid Infrastructure for Oracle Restart:
Before you attempt this you’ll need to deconfigure the Restart resources – and please be aware that here’s a small difference in commands between Oracle 12.1.0.2 and Oracle 12.1.0.1.
This is from the documentation for Oracle 12.1.0.2:
- Deconfigure Oracle Restart 12.1.0.2:
- Log in as root
-
# cd /u01/app/12.1.0.2/grid/crs/install # roothas.sh -deconfig -force
- Once this is complete you can now deinstall the Grid Infrastructure with the deinstall tool
- See the documentation
- Then you will need either to reinstall the previous – for instance Oracle 11.2.0.4 – Grid Infrastructure or – if it’s still present on the machine – reconfigure it by running root.sh from the previous Clusterware’s home
- And finally reconfigure the database(s) again with Clusterware
-
$ srvctl downgrade database -d db-unique-name -o oraclehome -t to_version
-
.
In case you’d plan to do this exercise back from Oracle 12.1.0.1 instead then you’ll have different steps to follow to deconfigure Oracle Restart 12.1.0.1:
- Deconfigure Oracle Restart 12.1.0.1
-
# cd /u01/app/12.1.0.1/grid/crs/install # /u01/app/12.1.0.1/grid/perl/bin/perl /u01/app/12.1.0.1/grid/crs/install/roothas.pl -deconfig
-
Regarding ASM backwards compatibility please be aware that changing the COMPATIBLE attributes within ASM will get you in trouble – see the Oracle Database Upgrade Guide for further information:
http://docs.oracle.com/database/121/UPGRD/afterup.htm#CEGJDCDD
–Mike
PS: See bug18160024 or the GI install guide, section A11.4 for the Standalone GI downgrade instructions from 12.1.0.2.0.
I just wanted when we deconfigure Oracle 12c restart, will ASM also gets downgraded ?
My understanding:
As long as you haven’t changed the COMPATIBLE setting of ASM it will start in the previous release.
Please check the upgrade guide:
http://docs.oracle.com/database/121/UPGRD/afterup.htm#CEGJDCDD
Cheers
Mike
Hi Mike,
If I don’t have a 12c database yet (I just installed/upgraded the GI to 12.1.0.2 using silent mode response file and found opatchauto is giving me trouble so I am going to downgrade, and using my 11g GI again, then reinstall/upgrade to 12.1.0.2 with GUI), do I have to run this last part in your post?
And finally reconfigure the database(s) again with Clusterware
$ srvctl downgrade database -d db-unique-name -o oraclehome -t to_version
Thanks!
Erin
Erin,
do you do Oracle Restart or do you have a real Cluster?
Cheers
Mike
reconfigure it by running root.sh. -> This will not help we need to reconfig has.