A financial analytics firm generates daily transaction summaries that are stored in an Ama… — AWS Certified Solutions Architect - Associate

A financial analytics firm generates daily transaction summaries that are stored in an Amazon S3 bucket. The summaries are accessed frequently by downstream applications for the first $30 \text{ days}$ after creation. After $30 \text{ days}$ , access to the summaries drops to almost zero, but they must be retained for compliance purposes for a total of $45 \text{ days}$ from creation. During the compliance retention period, the summaries must remain queryable within milliseconds. Which of the following lifecycle configurations represents the most cost-effective storage strategy for these summaries?

Keep the transaction summaries in S3 Standard for the entire $45 \text{ days}$ , then use a lifecycle rule to expire the objects.Answer
B
Transition the transaction summaries to S3 Standard-Infrequent Access (S3 Standard-IA) after $30 \text{ days}$ , and expire the objects after $45 \text{ days}$ .
C
Transition the transaction summaries to S3 Glacier Flexible Retrieval after $30 \text{ days}$ , and expire the objects after $45 \text{ days}$ .
D
Transition the transaction summaries to S3 Glacier Instant Retrieval after $30 \text{ days}$ , and expire the objects after $45 \text{ days}$ .

Answer

Keep the transaction summaries in S3 Standard for the entire 45 days, then use a lifecycle rule to expire the objects.

Keeping the files in S3 Standard for the entire duration is the most cost-effective solution because the storage duration in the lower tier (15 days) is shorter than the minimum billing threshold of S3 Standard-IA (30 days) and S3 Glacier Instant Retrieval (90 days). The cost of paying the minimum storage duration penalty makes transitioning the objects more expensive than maintaining them in the standard tier.

Step-by-Step Solution

Calculate the storage cost of keeping the summaries in S3 Standard for the entire

45 \text{ days}

The cost is approximately

\$0.0345

per GB.

S3 Standard charges

\$0.023

per GB-month. For

45 \text{ days}

, the prorated storage cost is

45 \text{ days} \times (\$0.023 / 30 \text{ days}) = \$0.0345

per GB.

Calculate the storage cost of transitioning the summaries to S3 Standard-IA at day 30 and expiring them at day 45.

The cost is approximately

\$0.0355

per GB plus transition request fees.

S3 Standard-IA has a minimum storage duration of

30 \text{ days}

. Transitioning at day 30 and deleting at day 45 means the objects spend only

15 \text{ days}

in S3 Standard-IA but are billed for

30 \text{ days}

. The cost is 30 days in S3 Standard (

30 \times \$0.023 / 30 = \$0.023

) plus 30 days of S3 Standard-IA (

30 \times \$0.0125 / 30 = \$0.0125

), totaling

\$0.0355

per GB.

Evaluate S3 Glacier options against retrieval time constraints and minimum storage duration rules.

S3 Glacier Flexible Retrieval fails the millisecond query requirement. S3 Glacier Instant Retrieval meets retrieval times but incurs a

90 \text{ day}

minimum storage charge, leading to a substantial early deletion penalty.

Glacier Flexible Retrieval requires minutes or hours for retrieval, which does not meet the millisecond requirement. Glacier Instant Retrieval has a minimum storage duration of

90 \text{ days}

, so deleting at day 45 forces a

75 \text{ day}

early deletion charge (

90 \text{ days} \times \$0.004 / 30 = \$0.0120

for storage, bringing total cost to

\$0.0350

per GB plus high transition request charges).

Key Concept

Minimizing storage costs by understanding minimum storage duration charges and retrieval latency constraints across S3 storage tiers.

Question

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

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