A meteorological modeling company runs daily simulations that generate two types of output… — AWS Certified Solutions Architect - Associate

A meteorological modeling company runs daily simulations that generate two types of output files stored in an Amazon S3 bucket:

* Raw simulation data: Files average $1.5\text{ GB}$ in size.
* Summary reports: Files average $20\text{ KB}$ in size.

Both file types are accessed frequently by the simulation team during the first $10\text{ days}$ following creation. After $10\text{ days}$ , the files are rarely accessed. All files must be retained for a total of $25\text{ days}$ and can be deleted thereafter.

Which S3 lifecycle configuration is the most cost-effective for this scenario?

A
Configure a lifecycle rule to transition the raw simulation data to S3 Standard-IA after 10 days, and expire all files after 25 days.
Configure a lifecycle rule to expire all files after 25 days, keeping them in S3 Standard for their entire lifecycle.Answer
C
Configure a single lifecycle rule to transition all files in the bucket to S3 Standard-IA after 10 days, and expire all files after 25 days.
D
Configure a lifecycle rule to transition the raw simulation data to S3 Glacier Instant Retrieval after 10 days, and expire all files after 25 days.

Answer

Configure a lifecycle rule to expire all files after 25 days, keeping them in S3 Standard for their entire lifecycle.

The correct option is to keep all files in S3 Standard and expire them after 25 days. Because the files are deleted after 25 days and transitioned after 10 days, they would only spend 15 days in the target storage class. S3 Standard-IA has a minimum storage duration of 30 days, meaning an early deletion fee for the remaining 15 days is applied. For the raw simulation data (

1.5\text{ GB}

), the combined cost of 10 days in S3 Standard and 30 days in S3 Standard-IA is higher than keeping them in S3 Standard for the full 25 days. Additionally, the

20\text{ KB}

summary reports are below the

128\text{ KB}

minimum billable size for S3 Standard-IA, which would result in paying for

128\text{ KB}

of storage per file.

Step-by-Step Solution

Analyze the file sizes, access patterns, and retention requirements.

The files consist of large raw simulation data (

1.5\text{ GB}

) and small summary reports (

20\text{ KB}

). They are accessed for

10\text{ days}

and must be deleted after

25\text{ days}

, meaning they would spend at most

15\text{ days}

in any transitioned storage tier.

Understanding the actual residency time in any lower storage tier is critical to assessing whether transition penalties will apply.

Calculate the S3 Standard-IA storage cost compared to S3 Standard.

For the raw simulation data (

1.5\text{ GB}

), S3 Standard-IA has a minimum storage duration of

30\text{ days}

. Deleting the files after

15\text{ days}

in S3 Standard-IA results in paying for

30\text{ days}

of storage. The cost of

10\text{ days}

in S3 Standard +

30\text{ days}

in S3 Standard-IA is higher than keeping the files in S3 Standard for the entire

25\text{ days}

S3 Standard-IA has a 30-day minimum storage duration, and violating it leads to early deletion charges.

Evaluate the impact of minimum billable object size on the summary reports.

The summary reports are

20\text{ KB}

in size. The minimum billable object size for S3 Standard-IA is

128\text{ KB}

. Transitioning these files to S3 Standard-IA would result in paying for

128\text{ KB}

of storage per file, which is significantly more expensive than keeping them in S3 Standard.

S3 Standard-IA is not cost-effective for files smaller than

128\text{ KB}

due to the minimum object size billing threshold.

Evaluate the S3 Glacier Instant Retrieval option.

S3 Glacier Instant Retrieval has a minimum storage duration of

90\text{ days}

. Storing files there for

15\text{ days}

and deleting them incurs a

75\text{ day}

early deletion penalty, which is highly cost-inefficient.

Glacier tiers are designed for long-term archiving and carry severe cost penalties for short retention periods.

Key Concept

Understanding S3 lifecycle transitions, minimum storage durations, and minimum object size limits to optimize costs.

Question

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

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