By Mike Dietrich-Oracle on Feb 15, 2012
This question got posted by Naveen in the previous entry today - and I found it worth it to create a new blog entry as this question gets raised in nearly every 2nd workshop as well - so others might be interested as well.
A question has been bothering me for a while and I thought I'll throw it out there. I didn't raise a support ticket, I knew what the response is going to be.
So here is the question. I have an 11g ORACLE HOME that was built as 184.108.40.206. Now if I want to upgrade to 220.127.116.11 or 18.104.22.168, I guess there is no easy way to upgrade the existing ORACLE HOME. Why didn't Oracle give the option to just apply a patch (opatch) and upgrade to 22.214.171.124 (or .3). For a customer to create a new ORACLE HOME is just a lot of work and breaks a lot of things. We have to copy over so many configs from the old home to the new home.
I'm sure there is a good reason, I'm just trying to understand what they are.
Naveen, thanks for your question. And the answer has many aspects.
Install into your existing ORACLE Home
First of all you can still install the new patch set (which is now a full release since Oracle 126.96.36.199) into your existing $ORACLE_HOME. But you'll have to detach your current home from the OUI's inventory first. Please see slide 41 of the Upgrade and Migration workshop deck. Please backup the contents of $ORACLE_HOME/dbs and $ORACLE_HOME/network/admin first as you'll have to copy them back later.
$ ./runInstaller -detachHome ORACLE_HOME=/u01/orahomes/11.2.0
Starting Oracle Universal Installer...
Checking swap space: must be greater than 500 MB. Actual 10047 MB Passed
The inventory pointer is located at /etc/oraInst.loc
The inventory is located at /u01/orabase
'DetachHome' was successful.
Once you've done that you'll install into your existing (old) directory. And finally you'll copy back your dbs and network/admin files.
Why customers might use this procedure?
There are basically two reason why a customer chooses this strategy:
(a) Home naming conventions not allowing an Oracle 188.8.131.52 home and another Oracle 184.108.40.206 home
(b) Space issues
Both are valid reasons and therefore you can stay with the old strategy.
Why did we change from patchsets to full release patchsets?
Simple reason: Customers did ask us for a looooong time why we are delivering 3GB large patchsets instead of full releases. So we'd follow this wish. And second it will decrease the overall downtime when you'd install into your new Oracle Home. If you apply patchset software to your existing Oracle Home every Oracle process serviced by that home must be shut down as well - obviously including the database(s). And furthermore if something fails you'll have to restore your OUI's inventory plus all home contents - or reinstall your previous Oracle software.
Besides that we recommend to patch this home first with important one-offs (see links in MOS Note 161818.1) and the latest PSU or CPU. If you'd do that to your already emptied old home it will simply increase again your overall downtime.
And this is the reason why we recommend:
Always install into a new Oracle home beginning with Oracle Database 11.2 - don't erase your old home to reuse it unless there's no significant need for that procedure.