To minimize downtime during patching of NON-RAC databases Out of Place Patching can be used. You can apply this approach to any Oracle patch starting from Oracle database 11g (126.96.36.199.0+) using OPatch utility. In this case time spent installing the software can be saved from the total database downtime required. However, some downtime is required for switching database services to the new Oracle database home and applying a post-upgrade script. A basic overview of the steps is below:
– Clone the existing database home online
– Apply required patch to the cloned database home using OPatch
– Switch the database services to the cloned database home
– Complete the post installation tasks for the patch applied
– Oracle database 11g and 12c documentation describe DB_HOME cloning only in OFFLINE mode (when DB is down)
– However, there should be no requirement to shutdown any databases, listeners, agents etc. that are running from the source home while cloning the Oracle Home directory because any processes that load the static binaries or libraries into memory should not hold a write lock.
– Oracle Out of Place patching is supported by SAP
– Out of Place patching is a recommended patching method that is used in out of the box deployment procedure of Oracle Enterprise Manager (OEM) Cloud Control 12c+ version
Below we will use a combination of Oracle documentation, a few MOS Notes and a little bit of experience to manually conduct Out of Place patching of Oracle database 12c
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Oracle database patching is one of the most frequently executed maintenance activities that every DBA does in his life. The task is fairly simple and straight forward using the patch instructions from My Oracle Support (MOS). However in this article I’d like to highlight the importance of different Patch Prerequisite Checks that you have to perform before doing the patching itself. I think the entire success of patching exercise depends mostly on this step as seen on the below table that represents major PSU patching steps and approximate time lines. The rest of this draft document describes some best practices, tips and code examples for doing patch prerequisite checks using OEM Cloud Control, MOS and OPatch utility. Comments, adjustments, other tips and ideas are welcome and will be included in this post.