S3 Versioning

5 minutes 5 Questions

Versioning in Amazon S3 allows preservation of multiple variants of an object. When enabled, each modification or deletion creates a new version of the object while preserving the previous ones. This makes it possible to recover from accidental overwrites or deletions. However, note that keeping multiple versions of objects increases storage costs.

A Comprehensive Guide to Amazon S3 Versioning and How to Ace it in Exams

Amazon S3 versioning is one of the most important aspects in AWS Solution Architect exams.

What is S3 Versioning?
Amazon S3 versioning is a feature offered by Amazon that allows you to store multiple variants of an object in the same bucket. With versioning, you can preserve, retrieve, and restore every version of every object.

Why is it important?
Amazon S3 versioning is crucial as it provides an additional layer of protection and ensures the continuity of your work in suspense of accidental deletions or modifications.

How does S3 Versioning work?
Once enabled, S3 Versioning keeps all versions of an object (including all writes and deletes) in the bucket. When you perform a DELETE operation, all versions remain in the bucket and Amazon S3 inserts a delete marker. So, any subsequent calls to GET the object will return a 404 not found error unless and until the delete marker is removed.

Exam Tips: Answering Questions on S3 Versioning:

Understand the concept: First and foremost, have a solid understanding of the concept and function of S3 Versioning.
Know how to enable it: Remember how to enable S3 Versioning as you may encounter questions about the process.
Consistency model: Be aware that Amazon S3 offers eventual consistency for overwrite PUTS and DELETES, but provides read-after-write consistency for PUTS of new objects.
Cost implications: Keep in mind that enabling versioning increases storage costs as all versions of an object are charged.
Delete markers: Understand the role of delete markers and how they can be managed.

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Question 1

A company stores private files in an S3 bucket with versioning enabled. They want to make sure that only authorized employees can access specific versions of these files. What should be implemented?

Enable S3 Transfer Acceleration for versioning control. Create a separate bucket for each object version. Use bucket policies to control access permissions to specific object versions. Use a lifecycle rule to move the object versions to Amazon Glacier Deep Archive.

Correct Answer: Use bucket policies to control access permissions to specific object versions.

Using bucket policies, you can define access permissions for specific object versions. The other answers involve incorrect features or would not control access to specific versions.

Question 2

A company stores important files in an S3 bucket with versioning enabled. They need to ensure that objects cannot be overwritten or deleted for a minimum of 30 days. What should be implemented?

Set an S3 event to trigger an AWS Lambda function to undelete objects. Apply a lifecycle policy to transition objects to Amazon S3 Glacier after 30 days. Enable S3 Inventory to track changes to objects. Enable S3 Object Lock with a default retention period of 30 days.

Correct Answer: Enable S3 Object Lock with a default retention period of 30 days.

Enabling S3 Object Lock with a default retention period of 30 days ensures that objects cannot be overwritten or deleted during that period. The other options do not specifically address preventing object modification for a minimum duration.

Question 3

A company stores project files in an S3 bucket with versioning enabled. However, it only wants to keep versions up to one year old to minimize storage costs. What should be done?

Use cross-region replication to move the older versions to a different AWS region. Enable S3 Intelligent-Tiering to minimize storage costs. Configure a lifecycle rule to move older versions to Glacier or delete them after one year. Enable Amazon S3 Select to filter out older versions.

Correct Answer: Configure a lifecycle rule to move older versions to Glacier or delete them after one year.

By configuring a lifecycle rule, you can define actions like moving older versions to Glacier or deleting them after a set period. The other answers suggested use unrelated features or won't be effective in minimizing storage costs.

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