CompTIA Server+ SK0-005 Practice Question

The correct answer is application-consistent replication. This method uses services like Microsoft's Volume Shadow Copy Service (VSS) to quiesce the application, ensuring that all data in memory and pending I/O operations are flushed to disk before the snapshot is taken. This creates a point-in-time replica that is transactionally consistent, allowing the database to be brought online quickly and without corruption after a failover.

• Crash-consistent replication only captures data that has been written to the disk, similar to the state after an unexpected power loss. It does not account for data in memory or pending transactions, which can lead to database corruption or a lengthy recovery process for transactional applications.
• Asynchronous replication is a timing method where data is written to the primary site first and then replicated to the secondary site with a slight delay. While often used in disaster recovery, it describes when data is replicated, not the state of the data's consistency. Replication can be both asynchronous and application-consistent, but "asynchronous" by itself does not guarantee the application's data is in a usable state.
• File-level replication copies individual files. This method is generally not suitable for live, high-transaction databases because database files are often locked, and it does not capture the complete transactional state, including in-memory data.