A static service must be registered with the local listener to enable DGMGRL to restart instances during the course of broker operations (A):For DGMGRL (Data Guard Manager Command-Line Interface) to perform instance management operations, such as restarting instances, a static service registration in the listener is required. This allows the broker to connect to the database instance even when the instance is not fully up and the dynamic service registration is not available.

Installing the oracle-database-preinstall-19c package is NOT sufficient to set up operating system kernel parameters for Oracle Net (C):While the oracle-database-preinstall-19c package automates the setting of several kernel parameters to meet the preinstallation requirements for Oracle Database, it does not specifically tailor all settings for Oracle Net in a Data Guard configuration. Additional manual configuration may be required to optimize Oracle Net services for Data Guard operations.