Selected Answer: BD B & D https://aws.amazon.com/premiumsupport/knowledge-center/trusted-advisor-cost-optimization/

C is stating "Reserved Instances" The question states they are using On Demand Instances. Reserved instances are reserved for less money for 1 or 3 years.

I would go with B and C as the company is running for 90 days and C option is basing on 30 days report which would mean that there is higher potential on cost saving rather than on idle instances

The answer is either BC or BD, depending on how you interpret "The company runs several active... instances for 90 days for 90 days." D: it assumes the instances will only run for 90 days, so reserved instances can't be the answer, since it requires 1-3 years utilization. C: it assumes there is no idle instances since they've been active for the last 90 days.

A: AWS Trusted Advisor recommendations for RDS cost optimization are only available within the AWS account where the instances are running. The consolidated billing (payer) account does not provide detailed service-level checks for linked accounts. Therefore, the finance team must access the Trusted Advisor check directly from the AWS account that owns the RDS instances to see relevant recommendations. C: The company has been using high-performance RDS instances for 90 days, which indicates a long-term workload. Reserved Instances (RIs) offer significant cost savings compared to On-Demand pricing when committing to one or three years. Trusted Advisor identifies instances with consistent usage and recommends RIs to reduce costs, making this the most relevant check for optimizing expenses. Even after 90 days, purchasing an RI for the remaining duration still provides substantial savings.

Reserved Instances are for 1 or 3 years. Not for 90 days

If you're choosing D for the idle instances, Amazon RDS Reserved Instance Optimization Trusted Advisor check includes recommendations related to underutilized and idle RDS instances. It helps identify instances that are not fully utilized and provides recommendations on how to optimize costs, such as resizing or terminating unused instances, or purchasing reserved instances to match usage patterns more efficiently.

"you can reserve a DB instance for a one- or three-year term". We only have data for 90 days. I feel it too risky to commit for 1/3 year(s) without information on future usage. If we knew that we expected the same usage pattern for the next 1,2,3 years, Id agree with C.

BD is the answer-Amazon Redshift Reserved Node Optimization and Relational Database Service (RDS) Reserved Instance Optimization check are not available to accounts linked in consolidated billing.

Chat AI - B: Wrong — payer account can’t see RDS instance-level Trusted Advisor checks for all linked accounts. D: Wrong — “Idle DB Instances” doesn’t apply here because the instances are explicitly described as active. E: Wrong — “Redshift Reserved Node Optimization” is for Redshift, not RDS.

Insights: The company runs several active high performance Amazon RDS for Oracle On-Demand DB instances for 90 days So it's clear that this company need to check the configuration of any Amazon Relational Database Service (Amazon RDS) for any database (DB) instances that appear to be idle.

D checks for instances that did not have a connection for a while, which is not the case here, all instances are active.

C is about optimizing on-demand instances by turning them into reserved instances.

In the scenario it says for 90 days, therefore the correct answer is D No C

B: Use the Trusted Advisor recommendations from the consolidated billing account to see all RDS instance checks at the same time. This option allows the finance team to see all RDS instance checks across all AWS accounts in one place. Since the company uses consolidated billing, this account will have access to all of the AWS accounts' Trusted Advisor recommendations. C: Review the Trusted Advisor check for Amazon RDS Reserved Instance Optimization. This check can help identify cost savings opportunities for RDS by identifying instances that can be covered by Reserved Instances. This can result in significant savings on RDS costs.

B&C AWS Trusted Advisor is an online resource to help you reduce cost, increase performance, and improve security by optimizing your AWS environment. (...) Recommendations are based on the previous calendar month's hour-by-hour usage aggregated across all consolidated billing accounts. https://docs.aws.amazon.com/whitepapers/latest/cost-optimization-reservation-models/aws-trusted-advisor.html Amazon EC2 Reserved Instance Optimization: An important part of using AWS involves balancing your Reserved Instance (RI) purchase against your On-Demand Instance usage. This check provides recommendations on which RIs will help reduce the costs incurred from using On-Demand Instances. We create these recommendations by analyzing your On-Demand usage for the past 30 days. We then categorizing the usage into eligible categories for reservations. https://docs.aws.amazon.com/awssupport/latest/user/cost-optimization-checks.html#amazon-ec2-reserved-instances-optimization

https://aws.amazon.com/premiumsupport/knowledge-center/trusted-advisor-cost-optimization/

B) Use the Trusted Advisor recommendations from the consolidated billing account to see all RDS instance checks at the same time. This option allows the finance team to see all RDS instance checks across all AWS accounts in one place. Since the company uses consolidated billing, this account will have access to all of the AWS accounts' Trusted Advisor recommendations. C) Review the Trusted Advisor check for Amazon RDS Reserved Instance Optimization. This check can help identify cost savings opportunities for RDS by identifying instances that can be covered by Reserved Instances. This can result in significant savings on RDS costs.

B.Trusted Advisor is account-scoped for most service checks, including RDS.You must view RDS recommendations in the account where the RDS instances actually run. C. Review the Trusted Advisor check for Amazon RDS Reserved Instance Optimization Reserved Instances are recommended when: Instances are running continuously, Usage is predictable

A. Use the Trusted Advisor recommendations from the account where the RDS instances are running. Trusted Advisor cost optimization checks for RDS (such as Reserved Instance Optimization and Idle DB Instances) are available in the account where the RDS resources are provisioned. The finance team must access the recommendations from the relevant account to see the checks for those specific RDS instances. C. Review the Trusted Advisor check for Amazon RDS Reserved Instance Optimization. This check analyzes your On-Demand RDS usage and recommends purchasing Reserved Instances to save costs. It is a key Trusted Advisor recommendation for reducing RDS costs, especially for workloads running for extended periods

The company run instances only for 90 days then reserved instances cannot save costs

Once read the question again, I agree with you.

The article emphasizes that Trusted Advisor generates recommendations at the individual AWS account level. While the consolidated billing account provides a centralized view of billing, the specific optimization recommendations for resources like RDS instances will be found within the account where those resources reside. The article also mentions checks for idle resources like "Amazon EC2 Idle Instances" and "Amazon RDS Idle DB Instances." However, as the original analysis pointed out, the scenario specifies that the RDS instances are active and running a high-performance application, making the "Idle DB Instances" check less relevant for the immediate goal of reducing costs for these specific instances.

Chat says answer A and C. May want to check it out yourself. Fairly good reasons for the answer.