Patch upgrade after Oracle11gR2

You can install the new OracleHome directory of OracleDatabase. After the installation is complete, the old database will be migrated to the new OracleHOME directory. This method is pushed by oracle

The new OracleHome directory for Oracle Database installation can be migrated to the new Oracle HOME directory after the installation is complete. This method is pushed by oracle

The following content is from the patchset document.

Oracle Database Patch Set Notes 11 gRelease 2 (11.2.0.3) Patch Set 2 E24903-01
Patch Set Overview
Oracle Database patch set, release 11.2.0.3 is a full installation of the Oracle Database software. this means that you do not need to install Oracle Database 11 gRelease 2 (11.2.0.1) before installing Oracle Database 11 gRelease 2 (11.2.0.3 ).
See Also:
"Oracle Database 11 gRelease 2 (11.2.0.3) New Features" inOracle Database New Features Guide
Note the following changes with the new patch set packaging:
New installations consist of installing the most recent patch set, rather than installing a base release and then upgrading to a patch release.
Direct upgrades from previous releases to the most recent patch set are supported.
Out-of-place patch set upgrades recommended, in which you install the patch set into a new, separate Oracle home. In-place upgrades are supported, but not recommended.

The patchset of 11.2.0.3 (including Oracle 11.2.0.2) is a complete installation package, so it can be directly used for installation.

In-Place Upgrade
This feature enables you to upgrade an existing installation of Oracle database to Oracle Database 11 gRelease 2 (11.2.0.3) into the same Oracle home directory by replacing the existing database files. the patch set application requires more downtime and is not recommended. this upgrade type requires less disk space.
Note:
If you select In-place upgrade to upgrade Oracle database to the latest version, then you must:
Review "Optionally connected Ming an In-Place Upgrade (Into the Same Oracle Home)" inOracle Database Upgrade Guide.
Take a complete backup of your Oracle home directory before you perform. the upgrade.

Installing the upgrade file to the original Oracle home Directory can save disk space, but requires more downtime. This method is not recommended for Oracle.

Out-of-Place Upgrade
This feature enables you want to install Oracle Database 11 gRelease 2 (11.2.0.3) in a new, separate Oracle home directory. after the installation is complete, the data from the database in the old Oracle home directory is migrated to the database in the new Oracle home directory.
Out-of-place upgrade process is similar to Oracle database upgrade from one version to another and is the recommended type. the benefits of this upgrade type is that the patch set application requires much less downtime, and is safer when the patch set application must be aborted. this upgrade type requires more disk space to accommodate two Oracle home directories simultaneously.

The new OracleHome directory for Oracle Database installation can be migrated to the new Oracle HOME directory after the installation is complete.
This method is recommended by oracle, which can reduce the downtime and be safer. However, this method requires at least twice the disk space.

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