SAA-C03 practice question: S3 storage classes and lifecycle (1 of 3)
Design Cost-Optimized Architectures A free question from our original SAA-C03 practice exam. Try it, then open the answer to see why each option is right or wrong.
A company stores application logs in Amazon S3, at about 5 MB per object.
Engineers read logs many times a day for the first 30 days. From day 30 to day 90, logs are read a few times a month and must still open in milliseconds. After 90 days, logs are almost never read, and a retrieval time of up to 48 hours is acceptable.
Logs must be deleted after 7 years.
Which solution is the MOST cost-effective?
Choose one answer.
AA. Add a lifecycle rule that moves logs to S3 Standard-IA after 30 days and to S3 Glacier Deep Archive after 90 days, and expires them after 7 years.
BB. Add a lifecycle rule that moves logs to S3 Standard-IA after 30 days and to S3 Glacier Flexible Retrieval after 90 days, and expires them after 7 years.
CC. Add a lifecycle rule that moves logs to S3 Glacier Flexible Retrieval after 30 days and to S3 Glacier Deep Archive after 90 days, and expires them after 7 years.
DD. Upload logs to S3 Intelligent-Tiering with the Deep Archive Access tier activated, and add a lifecycle rule that expires them after 7 years.
Show the answer and explanation
Answer: A
A. Right: Correct. Standard-IA gives millisecond access at a lower storage price for data read about once a month. Glacier Deep Archive is the lowest-cost storage class, and its bulk retrievals finish within 48 hours, which the company accepts. The expiration action deletes logs automatically after 7 years. Learn more: Understanding and managing Amazon S3 storage classes (opens in a new tab)
B. Wrong: This meets every access requirement, but Glacier Flexible Retrieval costs considerably more per GB than Glacier Deep Archive. Its faster retrievals are not needed when 48 hours is acceptable, and logs spend most of their 7 years in this last tier. Deep Archive is the cheaper final step. Learn more: Secure archive storage – Amazon S3 Glacier storage classes (opens in a new tab)
C. Wrong: Objects in Glacier Flexible Retrieval must be restored before they can be read, which takes minutes to hours. Logs between 30 and 90 days must open in milliseconds, so this breaks that requirement. Standard-IA keeps millisecond access for that period. Learn more: Understanding archive retrieval options (opens in a new tab)
D. Wrong: Intelligent-Tiering suits data whose access pattern is unknown, but it adds a monthly monitoring charge per object. Objects reach the Deep Archive Access tier only after at least 180 days without access, later than the 90 days possible here. With a known pattern, lifecycle rules are cheaper. Learn more: How S3 Intelligent-Tiering works (opens in a new tab)
Explanation
When the access pattern is known, S3 Lifecycle rules move each object to the cheapest class that still meets its access needs. Standard-IA covers days 30 to 90 with millisecond reads; Glacier Deep Archive covers the long tail because 48-hour retrieval is acceptable; and an expiration action deletes logs at 7 years. Intelligent-Tiering's monitoring fee pays off only when the pattern is unpredictable.
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