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SAA-012
You want to protect critical data stored in S3 against accidental deletion and be able to roll back to past states. Which feature is the most appropriate?
Choices
Explanation and answer
Read the explanation and correct answer (spoiler — try answering first)
Correct answer: A. S3 Versioning
Explanation
Enabling S3 Versioning preserves multiple versions of an object, which helps recover from accidental deletion or overwrites.
Per-choice explanations
A. S3 Versioning
Correct. Keeping previous versions improves recoverability.
B. S3 Transfer Acceleration
Incorrect. Transfer Acceleration speeds up uploads over long distances.
C. S3 Select
Incorrect. S3 Select retrieves only part of the data inside an object.
D. Only enable S3 Event Notifications
Incorrect. Event notifications alone cannot restore past objects.
Practical Use
S3 Versioning treats overwrite and delete operations against the same key as the creation of a new version, retaining previous versions. It is enabled at the bucket level, and after enablement every update and delete is stored as a version. If you accidentally call DeleteObject, the actual effect is that a Delete Marker is added; removing that marker restores the previous version. For production buckets that hold critical data, the standard design is to combine Versioning with MFA Delete and a lifecycle rule that periodically removes old versions. Alternatives include AWS Backup for S3 and cross-region replication (CRR) to another bucket. These follow a "make a copy in a different location" model, whereas Versioning is built around "retain past states within the same bucket." Versioning suits immediate recovery from accidental operations and overwrites, while CRR and Backup prepare for regional failures or logical destruction. After enabling Versioning, older versions are also billed, so a lifecycle policy that deletes or transitions them to Glacier-class storage after a certain period is required. On SAA-C03, Versioning is asked through phrases like "prepare for accidental deletion," "roll back to past states," or "retain object history." Distractors include "use a lifecycle policy to prevent deletion" or "S3 Object Lock alone can restore." Object Lock is a WORM (write once, read many) feature for tamper protection, while Versioning is the first choice for recovering from accidental operations.