Exam AWS Certified Solutions Architect - Professional SAP-C02 topic 1 question 311 discussion

EC2 - Saving Plan, MemoryDB - Reserved Node, Lambda - Compute Saving Plan

Answer is A, it saves the most cost saving option. B and D are out as reserved concurrency doesn’t help for cost saving. Compared between A&C, A is more cost effective solution, additionally compute saving plan doesn’t cover costs for elastic cache node.

A This solution addresses each component of the application separately: Purchasing an EC2 instance Savings Plan (Option A) provides a discounted rate for EC2 instances, which are experiencing continuous and stable load. Buying a Compute Savings Plan for Lambda (Option A) covers the minimum expected consumption of the Lambda functions, which have unpredictable and varied load. This plan type is specifically designed for workloads with varying usage patterns. Purchasing reserved nodes to cover the MemoryDB cache nodes (Option A) provides a discounted rate for the cache layer, which has stable and predictable load.

A makes sense. Reserved concurrency for Lambda doesn't address cost savings nor varied load. And compute plans don't cover MemoryDB. Reserved nodes should work.

Compute Saving Plans don't cover MemoryDB

We don’t know the expected load of Lambda so B and D out (it says expected Lambda usage) and A it’s more cost effective than C

A is most cost effective.

Reserved concurrency for lambda wont reduce costs, and lambda will benefit from compute savings plan https://aws.amazon.com/about-aws/whats-new/2020/02/aws-lambda-participates-in-compute-savings-plans/

ChatGPT

EC2 - Saving Plan, MemoryDB - Reserved Node, Lambda - reserved concurrency