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Question

Difficulty: HardCost-Optimized Storage Tiering and Lifecycle Management

A genomics research institute runs sequencing pipelines on AWS and stores its output files in an Amazon S3 bucket. The data consists of two distinct categories:

* Alignment files (`.bam`): These files average `250250 MB` in size. They are accessed frequently during the first `1010 days` of a run, after which they are rarely accessed. They must be kept for exactly `4545 days` for quality control and then deleted.
* Variant call files (`.vcf`): These files average `6060 KB` in size. They are accessed less than once a year, but they must be retained permanently for compliance and must be available within minutes when requested.

Which combination of actions will meet these requirements in the most cost-effective manner? (Select TWO.)

  1. Create an S3 Lifecycle rule to transition the alignment files to S3 Standard-Infrequent Access (S3 Standard-IA) after `1010 days`, and expire the files after `4545 days`Answer
  2. B
    Create an S3 Lifecycle rule to transition the alignment files to S3 Standard-Infrequent Access (S3 Standard-IA) after `1010 days`, and expire the files after `2525 days`
  3. Create an S3 Lifecycle rule to transition the variant call files to S3 Glacier Flexible Retrieval after `3030 days`Answer
  4. D
    Create an S3 Lifecycle rule to transition the variant call files to S3 Standard-Infrequent Access (S3 Standard-IA) after `3030 days`
  5. E
    Create an S3 Lifecycle rule to transition the variant call files to S3 Glacier Deep Archive after `3030 days`

Answer

The most cost-effective actions are: transition the alignment files to S3 Standard-IA after `1010 days` and expire them after `4545 days`; and transition the variant call files to S3 Glacier Flexible Retrieval after `3030 days`.
Transitioning the alignment files to S3 Standard-IA after `1010 days` and deleting them after `4545 days` is optimal because the files stay in S3 Standard-IA for `3535 days` (exceeding the `3030-day` minimum storage duration requirement), and their large size (`250250 MB`) avoids any minimum billing size penalties. Transitioning the variant call files to S3 Glacier Flexible Retrieval after `3030 days` is optimal because their size (`6060 KB`) exceeds Glacier's `4040 KB` minimum billing size, and Glacier Flexible Retrieval's Expedited retrieval option recovers files in `11 to 55 minutes`, meeting the requirement to access data within minutes.

Step-by-Step Solution

1
Evaluate lifecycle properties of the alignment files (`.bam`).
The files are `250250 MB` (exceeding S3 Standard-IA's `128128 KB` minimum billing size). Transitioning to S3 Standard-IA at day `1010` and expiring at day `4545` keeps the files in Standard-IA for `3535 days`.
Because the files reside in S3 Standard-IA for more than the `3030-day` minimum storage duration requirement, this transition is highly cost-effective and does not incur early deletion fees.
2
Evaluate lifecycle properties and access requirements of the variant call files (`.vcf`).
The files are `6060 KB`. Transitioning them to S3 Standard-IA or S3 Glacier Instant Retrieval would trigger a `128128 KB` minimum billing size penalty. S3 Glacier Flexible Retrieval has a `4040 KB` minimum billing size and supports Expedited retrievals (`11 to 55 minutes`).
Glacier Flexible Retrieval accommodates the `6060 KB` size without size-based billing overhead, keeps storage costs low for permanent retention, and satisfies the requirement to retrieve the files within minutes.
3
Select the two optimal lifecycle actions.
Transition alignment files to S3 Standard-IA after `1010 days` and expire after `4545 days` (Action 1). Transition variant call files to S3 Glacier Flexible Retrieval after `3030 days` (Action 2).
This combination minimizes storage costs by matching the workload requirements while avoiding size and duration penalties.

Key Concept

Aligning S3 Object sizes and lifecycle durations with the minimum billing sizes and minimum storage periods of S3 storage classes to avoid unexpected fees.
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Topics

Cost-Optimized Storage Tiering and Lifecycle Management