Oracle recommends that you use Cluster Verification Utility (CVU) to help to ensure that your upgrade is successful.

You can use CVU to assist you with system checks in preparation for starting an upgrade. CVU runs the appropriate system checks automatically, and either prompts you to fix problems, or provides a fixup script to be run on all nodes in the cluster before proceeding with the upgrade.

• About the CVU Grid Upgrade Validation Command Options
  You can use the Cluster Verification Utility (CVU) to validate your system readiness before upgrading.
• Example of Verifying System Upgrade Readiness for Grid Infrastructure
  You can use the runcluvfy.bat command to check your system before upgrading.