AWS Certified SysOps Administrator Practice Exam

Which statement is correct regarding EBS volumes and instance store-backed instances?

1. All instance store data is retained after termination

2. EBS snapshots capture only written data, excluding cached data

3. Separate EBS volumes are not needed for operating system and data

4. Data on non-root EBS volumes is lost during instance shutdown

The correct answer is: EBS snapshots capture only written data, excluding cached data

The selected statement highlights an important aspect of Amazon Elastic Block Store (EBS) snapshots. When a snapshot is taken, it captures the current state of EBS volumes, including only the data that has been written to disk. Notably, any data that resides in cache and has not been persisted to the disk is not included in the snapshot. This approach optimizes storage, as the snapshot reflects only the required information needed for restoration. Understanding this helps in effectively managing data persistence and backup strategies, ensuring that critical information is reliably stored and recoverable. Other statements may seem plausible but contain inaccuracies. For instance, instance store data is ephemeral, meaning it does not persist after an instance termination. Similarly, while it's true that you can use a single EBS volume for both the operating system and data, it is often best practice to use separate volumes for optimal performance and management. Finally, non-root EBS volumes maintain their data even during instance shutdown, demonstrating the reliable persistence of EBS outside of transient storage solutions like instance store.