To fulfill data-at-rest encryption requirements for a database, what is the best solution?

The requirement for data-at-rest encryption specifically pertains to securing data when it is stored and not actively being transmitted over a network. Among the options provided, creating a virtual encrypted disk and having the database write to it is the most appropriate solution for ensuring that the data within the database remains encrypted while it is stored.

Implementing a virtual encrypted disk ensures that all data written to it is automatically encrypted, effectively protecting sensitive information even if the underlying storage media is compromised. This solution addresses data-at-rest encryption requirements comprehensively, as it encrypts the files directly on the disk where the database stores its data. This method not only aids in fulfilling compliance needs concerning the protection of sensitive data but also simplifies management and ensures data confidentiality.

In contrast, installing an SSL certificate relates to securing data in transit, thus it doesn't meet the criteria for data-at-rest encryption. Enabling two-factor authentication enhances the security during login and access but does not protect the actual stored data. Activating memory encryption on a virtual server is beneficial during runtime operations but does not address the security of stored data effectively. Therefore, creating an encrypted disk is the best approach to meet the data-at-rest encryption requirement for a database.