Oracle ASM rolling upgrade enables you to independently upgrade or patch clustered Oracle ASM nodes without affecting database availability, thus providing greater uptime. Rolling upgrade means that some features of a clustered Oracle ASM environment continue to function when one or more of the nodes in the cluster uses different software versions. Oracle recommends that you perform an Oracle ASM rolling upgrade when performing an Oracle Clusterware rolling upgrade.
To perform a rolling upgrade, your environment must be prepared. Oracle Clusterware must be fully upgraded to the next patch or release version before you start the Oracle ASM rolling upgrade. In addition, you should prepare your Oracle Clusterware in a rolling upgrade manner to ensure high availability and maximum uptime.
Note that Oracle ASM is upgraded with Oracle Clusterware for Oracle 11g Release 2 (11.2) or later as both are in the Oracle Grid Infrastructure home.
Rolling upgrades only apply to clustered Oracle ASM instances, and you can only perform rolling upgrades on environments with Oracle Database 11g or later. You cannot use this feature to upgrade from Oracle Database 10g to Oracle Database 11g.
See Oracle Exadata documentation for information about performing a rolling upgrading of an Oracle ASM instance when Oracle Exadata storage is present.
Oracle Grid Infrastructure Installation Guide for information about performing, and restrictions related to, a rolling upgrade of Oracle ASM
Oracle Database Upgrade Guide for information about upgrading Oracle Database
Oracle Database SQL Language Reference for information about the rolling migration clause of the ALTER SYSTEM command