Exam AWS Certified Solutions Architect - Professional SAP-C02 topic 1 question 4 discussion

C. - Aurora writers is a distractor. - Single master mode only has read replica - with Aurora replicas. - Multi master mode, not in the options - NLB does not support round robin and least outstanding algorithm https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/Aurora.Integrating.AutoScaling.html

The best solution to provide a consistent user experience that will allow the application and database tiers to scale would be option C: C. Enable Aurora Auto Scaling for Aurora Replicas. Use an Application Load Balancer with the round robin routing and sticky sessions enabled. This solution involves enabling Aurora Auto Scaling for Aurora Replicas to automatically add and remove read replicas to match the application's workload. The solution also uses an Application Load Balancer to distribute traffic to the application layer, with the round robin routing algorithm to balance the traffic evenly across multiple instances. Sticky sessions should be enabled to maintain session affinity for each user, allowing for a consistent user experience.

Enable Aurora Auto Scaling for Aurora Replicas. Use an Application Load Balancer with the round robin routing and sticky sessions enabled

C is correct. This solution will provide a consistent user experience by using an Application Load Balancer with the round robin routing algorithm and sticky sessions enabled. This allows the application and database tiers to scale by using Aurora Auto Scaling for Aurora Replicas. This will ensure that the application is able to handle the increased user base while maintaining a consistent user experience. The use of an Application Load Balancer also allows for better routing of traffic to the available Aurora Replicas.

- Auto Scaling for Aurora writers does not exists (distractor) - NLB does not support least outstanding requests routing algorithm (it only supports Flow Hash) - NLB does not allow to enable Sticky Sessions, this is always enabled with Flow Hash where each TCP/UDP connection is routed to a single target for the life of the connection Thus C is correct

Option A - Allows the tiers to grow but NLB does not make load balancing decisions that way Option B - No such thing as Aurora Autoscaling for Aurora Writers Option C - Allows the tiers to grow and ALB using sticky sessions provides consistent user experience Option D - No such thing as Aurora Autoscaling for Aurora Writers Note: The application is web-based so choosing ALB shouldn't be an issue.

D. Enable Aurora Scaling for Aurora writers. Use a Network Load Balancer with the least outstanding requests routing algorithm and sticky sessions enabled.

C, Enable Aurora Auto Scaling for Aurora Replicas

C, Enable Aurora Auto Scaling for Aurora Replicas

Single writer: In an Aurora PostgreSQL DB cluster, there is only one writer instance at a time. All write operations, such as INSERT, UPDATE, and DELETE statements, are directed to the writer instance.

It's C

B, D are distractor, as there is no writer replica in aurora autoscale. NLB does not support sticky session so A is out. The anwser is C.

C Auto Scaling for Aurora Replicas. Use an Application Load Balancer with the round robin routing and sticky session

Aurora - AS only for read replicas. NLB doesn't support the least outstanding requests or round-robin algorithms, only flow hash is supported.

C. Enable Aurora Auto Scaling for Aurora Replicas. Use an Application Load Balancer with the round robin routing and sticky sessions enabled.

NLB scales better than ALB. Also least outstandind requests algorithm works better than round robin algorith. Any thougts?

write replica is distractor. NLB does not support round robin