Ensuring that backup copies of the database are also encrypted When encrypting a database for Tableau Server, it is crucial to ensure that backup copies of the database are also encrypted. This prevents scenarios where encrypted data at rest could be compromised through un-encrypted backups, maintaining a consistent level of security for all stored data, whether it is in active use or backed up. Option A is incorrect because while processing power is important for overall performance, it is not the primary concern for ongoing data security in the context of database encryption. Option C is incorrect as network monitoring, while important for security, does not ensure the encryption of data at rest or in backups. Option D is incorrect because setting up a redundant database server focuses on availability and does not directly address the encryption of data or back-ups.