You can configure the OKV_HOME environment variable at the instance level. This is useful if you have multiple instances on the same client, and each requires its own OKV_HOME definition to point to the Oracle Key Vault home directory. This is needed to run utilities, such as RMAN, if they need to access the Oracle Key Vault for keys.
Use the <INSTANCE_NAME>_CUSTOMIZED_ENV additional setting to define the OKV_HOME environment variable at the instance level. For more information, see Defining Instance-Specific Environment Variables.