Exam AWS Certified Solutions Architect - Professional topic 1 question 97 discussion

One logon for 5mil users using S3+DDB vs DDB alone DDB Alone: 1 logon retrieves 50kb data that consumes ~12 rcu total rcu consumed for 5 mil logons = 60 mil cost for 1 mil rcu = 0.25. total cost = .25*60 = $15 DDB + S3: 1 logon retrieves less than 4kb data so consumes 1 rcu of DDB 5 mil logon consume 5 mil rcu DDB cost = 5*.25 = $1.25 S3: total read requests = 5mil 1000 read requests cost 0.0004 5 mil read requests cost 5000*.0004 =$2 Total cost = $2+$1.25= $3.25 So DDB+S3 is more cost effective. So answer should be D.

D:(cost-effective, highly available, scalable and secure.) HA and scalable: S3 Secure: S3 ACL Cost-effective 5,000,000 * 50 KB = 250 GB DynamoDB Storage Cost = 0.25/GB * 250 = $62.50 S3 Storage = $0.03/GB * 250 = $7.50 So S3 is ~10% Cost of DDB but in the grant scheme of things,

Answer is D. Smart combination of S3 + DyDB

D. Store the user preference data in S3 Setup a DynamoDB table with an item for each user and an item attribute pointing to the user' S3 object. The mobile application will retrieve the S3 URL from DynamoDB and then access the S3 object directly utilize STS, Web identity Federation, and S3 ACLs to authenticate and authorize access.

Option D might seem more cost-effective at first glance, but it could lead to higher costs in the long run. This is because every time the user preferences are accessed, two separate requests are made: one to DynamoDB and another to S3. This could result in higher operation costs over time. Moreover, this approach could also lead to higher latency because you are making two separate network calls, which could negatively impact the user experience. On the other hand, Option B stores all data in DynamoDB and allows for direct querying. This reduces the need for multiple requests and can provide a faster, more efficient service. Plus, DynamoDB is designed for high availability and scalability, which makes it a good fit for this scenario. Remember, when designing a solution, it’s important to consider not just the immediate costs but also the long-term implications in terms of performance, scalability, and user experience.

I select B as I feel that security is more important than cost-effective. I prefer to improve D with *signed* S3 URLs. The FGA solution can be used in D too. The S3 ACL is not a secure approach for each of the mobile users, but it is good enough to secure S3 access by the signer.

B, this one is in the book "AWS Certified Solutions Architect Associate (SAA) 2021 | 15 Mock Tests For Complete Preparation"

B. Setup a DynamoDB table with an item for each user having the necessary attributes to hold the user preferences. The mobile application will query the user preferences directly from the DynamoDB table. Utilize STS. Web Identity Federation, and DynamoDB Fine Grained Access Control to authenticate and authorize access.

I go with B

Should be D. 50KB record consume Dynamodb rcu/wcu a lot. Not cost effective.

Correct Option is B https://youtu.be/uAUYphLWL5w

D. The question asks for cost-effective solution. D is most cost-effective and also highly available, scalable and secure. Though B is much easier for devekopers.

B is correct

Sound likes B

B http://jayendrapatil.com/aws-storage-options-whitepaper/