Oracle 11g Release 2: Oracle Clusterware Upgrade - Out-of-Place

Oracle clusterware 11g release 2 only supports out-of-place upgrade. It means that the new software is installed in different Oracle Clusterware home directory. Till now, in-place upgrade was available. In-place upgrade is nothing but it is installed in the same home directory and used as an existing or active software. Now with the help of out-of-place upgrade, both the version i.e. the existing one and the new one are installed and available on the nodes at the same time but in different Grid home. Any one can be the active software.

The advantage of out-of-place upgrade is to decrease the planned outage time required for the cluster upgrades, which helps in meeting the availability of service level agreement (SLA). Once the software is installed we can upgrade the cluster by stopping the previous version of the software and starting the new version node by node which is also known as a rolling upgrade.

To check the software version that indicates the version of the Oracle clusterware that is active on the server we can use $crsctl query crs activeversion. The software version is stored in the OCR. We also have a clusterwide "active version" for the entire cluster that reflects the version of the communication protocols and shared disk data structure that is currently used on the cluster.

Hope this topic will help you out understand Out-of-Place upgrade.