Update Oracle Homes Using Patched Oracle Homes

The following section highlights how Oracle Homes can be switched to other patched Oracle Homes with least amount of downtime.

Database Type	Steps Performed
Single Instance	Target is put in Blackout mode. Configuration files like: `spfile`, `password`, `listener.ora`, `sqlnet.ora`, `tnsnames.ora` are copied over to the patched Home. `oratab` file entries are updated Instance is brought down and brought up from the patched home. Target is brought of Blackout mode. For pre-12c databases SQLs are run using SQL*Plus. For 12c and higher databases, the Datapatch utility is called to make data changes.
Grid Infrastructure	All relevant targets are put in Blackout mode. Backup CRS configuration files from the source home directory: `$SRC_HOME/crs/utl/crsconfig_dirs`. Configuration files like: `spfile`, `password`, `listener.ora`, `sqlnet.ora`, `tnsnames.ora` are copied over to the patched Home. `oratab` file entries are updated HAS Instance, ASM Instance, Management database instance, Scan Listeners and Grid Listeners and all database instances are brought down and brought up with Patched Home as new Oracle Homes. Configuration scripts are run. All targets are brought out of Blackout mode. If the management database is used, pre-12c databases SQLs are run using SQL*Plus. For 12c and higher databases, the Datapatch utility is called to make data changes..
RAC Rolling Node	For each node: Target is put in Blackout mode. Configuration files like `spfile`, `password`, `listener.ora`, `sqlnet.ora`, `tnsnames.ora` are copied over to the patched Home. `oratab` file entries are updated Instance is brought down and brought up with Patched Home as new Oracle Home. Target is brought out of Blackout mode. For pre-12c databases SQLs are run using SQL*Plus. For 12c and higher databases, the Datapatch utility is called to make data changes.
RAC Non-Rolling Node	All RAC nodes are put in Blackout mode. Configuration files like `spfile`, `password`, `listener.ora`, `sqlnet.ora`, `tnsnames.ora` are copied over to the patched Home. `oratab` file entries are updated Instance is brought down and brought up with Patched Home as new Oracle Home concurrently. For pre-12c databases SQLs are run using SQL*Plus. For 12c and higher databases, the Datapatch utility is called to make data changes.