A genomic research institute runs weekly analysis pipelines that generate two types of fil… — AWS Certified Solutions Architect - Associate

A genomic research institute runs weekly analysis pipelines that generate two types of files stored in a single Amazon S3 bucket:

- Raw genomic sequence files: These files average $250\text{ MB}$ in size. They are processed immediately upon upload. After the first $10\text{ days}$ of processing, they are rarely accessed, but when requested, they must be retrieved within $5\text{ hours}$ . These files must be retained for a total of $120\text{ days}$ .
- Daily analysis logs: These files average $15\text{ KB}$ in size. They are accessed frequently during the first $30\text{ days}$ , after which they are accessed only occasionally for audit purposes. The logs must be retained for a total of $90\text{ days}$ .

Which TWO actions should a solutions architect recommend to store these files in the most cost-effective manner?

Transition the raw genomic sequence files from S3 Standard to S3 Glacier Flexible Retrieval after $10\text{ days}$ using an S3 Lifecycle policy.Answer
Retain the daily analysis logs in S3 Standard for the entire $90\text{ days}$ , rather than transitioning them to S3 Standard-IA.Answer
C
Transition the daily analysis logs to S3 Standard-IA after $15\text{ days}$ and configure an S3 Lifecycle policy to delete them after $25\text{ days}$ .
D
Transition the raw genomic sequence files to S3 Glacier Instant Retrieval after $10\text{ days}$ .
E
Transition the raw genomic sequence files to S3 Standard-IA after $10\text{ days}$ and then to S3 Glacier Deep Archive after $30\text{ days}$ .

Answer

The solutions architect should recommend transitioning the raw genomic sequence files from S3 Standard to S3 Glacier Flexible Retrieval after

10\text{ days}

, and retaining the daily analysis logs in S3 Standard for the entire

90\text{ days}

lifecycle.

The correct strategy transitions the large raw genomic sequence files to S3 Glacier Flexible Retrieval after

10\text{ days}

because it satisfies the

5

-hour retrieval window at a lower cost than S3 Glacier Instant Retrieval and exceeds the

90

-day minimum storage duration constraint. It also retains the small daily analysis logs in S3 Standard because transitioning files smaller than

128\text{ KB}

to S3 Standard-IA results in paying for the minimum

128\text{ KB}

storage limit, which is less cost-effective than keeping them in S3 Standard.

Step-by-Step Solution

Analyze the access pattern and size of the raw genomic sequence files.

The files are large (

250\text{ MB}

) and require retrieval within

5\text{ hours}

after

10\text{ days}

of active use. They must be kept for

120\text{ days}

total.

This helps select the most cost-effective archive tier that meets the

5

-hour retrieval window without violating minimum storage duration rules.

Compare S3 storage classes for the genomic sequence files.

S3 Glacier Flexible Retrieval supports

3-5

hour retrievals, has a

90

-day minimum duration, and has a very low storage cost. Storing them in Glacier Flexible Retrieval for

110\text{ days}

meets the

120

-day total retention and avoids early deletion charges.

Choosing Glacier Flexible Retrieval over Glacier Instant Retrieval or Glacier Deep Archive minimizes costs while adhering to retrieval and retention constraints.

Analyze the access pattern and size of the daily analysis logs.

The files are very small (

15\text{ KB}

), accessed frequently for

30\text{ days}

, and kept for

90\text{ days}

total.

Small file sizes require careful consideration of the S3 Standard-IA

128\text{ KB}

minimum billing size constraint.

Evaluate the cost impact of transitioning the daily analysis logs to S3 Standard-IA.

Because S3 Standard-IA bills a minimum of

128\text{ KB}

per object, transitioning

15\text{ KB}

files would result in paying for

128\text{ KB}

of storage, which is more expensive than keeping them in S3 Standard for the entire

90\text{ days}

Determining that keeping the files in S3 Standard is the most cost-effective choice for small objects.

Key Concept

Cost optimization in S3 requires evaluating both object sizes (to avoid the

128\text{ KB}

minimum billing size penalty of S3 Standard-IA) and storage durations (to avoid minimum storage duration penalties like the

30

-day minimum for S3 Standard-IA or

90

-day minimum for S3 Glacier Flexible Retrieval).

Question

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Topics