You can apply patches in a clustered Oracle ASM environment to update one node at a time to the latest patch level without affecting the overall availability of the Oracle ASM cluster or the database clusters using Oracle ASM for storage.
The ALTER SYSTEM ROLLING PATCH SQL statement enables you to start and stop rolling patches. For example:
SQL> ALTER SYSTEM START ROLLING PATCH; SQL> ALTER SYSTEM STOP ROLLING PATCH;
You can determine if the cluster is in rolling patch mode by executing a SYS_CONTEXT SQL query for Cluster State. A new state (In Rolling Patch) is added to informing the user that the cluster is in rolling patch mode.
The queries in Example 3-2 display information about rolling patches. To run these queries, you must be connected to the Oracle ASM instance in the Grid home, and the Grid Infrastructure home must be configured with the Oracle Clusterware option for an Oracle RAC environment.
You can view all the patch Ids applied on the node and cluster by querying the V$PATCHES view.
ASMCMD commands for rolling patches include:
showclusterstate
showpatches
showversion
For information about ASMCMD commands to monitor upgrade operations on an Oracle ASM instance, refer to "ASMCMD Instance Management Commands".
Oracle Database SQL Language Reference for information about the rolling patch clause of the ALTER SYSTEM command
Oracle Grid Infrastructure Installation Guide for information about performing, and restrictions related to, a rolling migration of Oracle ASM and Oracle Grid Infrastructure homes