Understand how you can prepare an Oracle Real Application Clusters (Oracle RAC) database for patch updates or upgrade.

• Backing Up the Oracle RAC Database
  Before you make any changes to the Oracle software, Oracle recommends that you create a backup of the Oracle Database installation.
• Using CVU to Validate Readiness for Oracle RAC Upgrades
  Review the contents in this section to validate that your Oracle RAC cluster is ready for upgrades.