A genomics research company stores two types of data in an Amazon S3 bucket:

- Raw DNA sequence data: The files average $350\text{ MB}$ in size. They are accessed frequently during the first $10\text{ days}$ after upload. Afterward, they are rarely accessed, but must be retained for a total of $25\text{ days}$ from the upload date before they can be safely deleted.
- Variant call metadata: The files average $30\text{ KB}$ in size. They are accessed frequently for the first $15\text{ days}$ after upload. Afterward, they are rarely accessed, but must be retained for a total of $90\text{ days}$ from the upload date before they can be safely deleted.

Which Amazon S3 lifecycle configuration is the most cost-effective for managing these datasets?

A
Transition the raw DNA sequence data to S3 Standard-IA after $10\text{ days}$ and delete them after $25\text{ days}$ ; transition the variant call metadata to S3 Standard-IA after $15\text{ days}$ and delete them after $90\text{ days}$ .
B
Transition the raw DNA sequence data to S3 Standard-IA after $10\text{ days}$ and delete them after $25\text{ days}$ ; keep the variant call metadata in S3 Standard and delete them after $90\text{ days}$ .
Keep both the raw DNA sequence data and the variant call metadata in S3 Standard for their entire lifetimes, and delete the raw data after $25\text{ days}$ and the metadata after $90\text{ days}$ .Answer
D
Keep the raw DNA sequence data in S3 Standard and delete them after $25\text{ days}$ ; transition the variant call metadata to S3 Standard-IA after $15\text{ days}$ and delete them after $90\text{ days}$ .

Answer

Keep both the raw DNA sequence data and the variant call metadata in S3 Standard for their entire lifetimes, and delete the raw data after

25\text{ days}

and the metadata after

90\text{ days}

The correct answer is to keep both the raw DNA sequence data and the variant call metadata in S3 Standard for their entire lifetimes. The raw DNA sequence data has a total lifecycle of 25 days. Transitioning it to S3 Standard-IA after 10 days would mean storing it in the IA tier for only 15 days, which violates the 30-day minimum storage duration of S3 Standard-IA and triggers a billing penalty. The variant call metadata files average 30 KB, which is well below the 128 KB minimum object capacity charge for S3 Standard-IA. Storing them in S3 Standard-IA would result in a significant capacity billing penalty.

Step-by-Step Solution

Analyze the lifecycle constraints for the raw DNA sequence data.

The files are

350\text{ MB}

(above the

128\text{ KB}

S3 Standard-IA minimum object size limit) and have a total lifetime of

25\text{ days}

Determining file size and duration is necessary to identify potential S3 Standard-IA storage tiering options.

Evaluate S3 Standard-IA transition feasibility for the raw DNA sequence data.

If transitioned to S3 Standard-IA at Day 10, the files remain in S3 Standard-IA for only

15\text{ days}

(

25 - 10

) before deletion. Because S3 Standard-IA has a minimum storage duration of

30\text{ days}

, the company will be billed for a full

30\text{ days}

of Standard-IA storage, making this transition financially suboptimal compared to remaining in S3 Standard.

Applying the S3 Standard-IA minimum storage duration rules reveals the storage cost penalty.

Analyze the lifecycle constraints for the variant call metadata files.

The metadata files average

30\text{ KB}

in size and have a total lifetime of

90\text{ days}

Understanding the characteristics of the second dataset is necessary to determine the optimal lifecycle configuration.

Evaluate S3 Standard-IA transition feasibility for the variant call metadata.

S3 Standard-IA has a minimum capacity charge of

128\text{ KB}

per object. Storing

30\text{ KB}

files in S3 Standard-IA forces billing at

128\text{ KB}

per file (a

326\%

increase in billed capacity), which negates standard storage tier savings.

Applying S3 Standard-IA minimum object size rules demonstrates that transitioning these small objects is more expensive than leaving them in S3 Standard.

Key Concept

S3 Lifecycle Management Cost Constraints

Question

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Topics