S3 Lifecycle rule not applying

Based on the information provided, there are a few potential reasons why your S3 Lifecycle rule may not be applying as expected:

1. Timing: S3 Lifecycle rules are not instantaneous. Amazon S3 typically evaluates and applies lifecycle rules once per day, starting at midnight UTC. It can take up to 24-48 hours for changes to take effect after creating or modifying a rule.

2. Object size: Amazon S3 does not transition objects smaller than 128 KB from S3 Standard or S3 Standard-IA storage classes to other classes. Ensure your objects meet this minimum size requirement.

3. Rule configuration: Double-check that your rule is correctly configured and enabled. The screenshot shows the rule is set to transition current versions after 0 days, which is correct for archiving existing objects.

4. Object eligibility: Verify that the objects in your bucket match the rule's filter criteria. If you've specified any prefix or tags in the rule, ensure your objects meet these conditions.

5. Permissions: Confirm that the S3 service has the necessary permissions to perform the transition operation. Check your bucket policies and IAM roles to ensure there are no restrictions preventing S3 from transitioning objects.

To troubleshoot:

1. Wait at least 48 hours after creating the rule to allow time for S3 to process it.
2. Use CloudWatch metrics or the AWS Billing and Cost Management console to monitor object transitions by storage class.
3. Check CloudTrail logs for any "AccessDenied" errors related to S3 Lifecycle operations.

If the issue persists after these checks, consider contacting AWS Support for further assistance with your specific bucket configuration.

Sources
S3 lifecycle rule is not applied: Standard -> Standard-AI | AWS re:Post
Troubleshooting Amazon S3 Lifecycle issues - Amazon Simple Storage Service