Use ElastiCache to reduce reading and choose redis to ensure high availability.

A vs B: A: reduce the number of database reads on main + high availability provide B: only reduce the number of DB reads so A wins

why not read replica when you get read performant with HA?

Options B, C, and D are not directly related to ensuring high availability

I think it is B: https://aws.amazon.com/getting-started/hands-on/boosting-mysql-database-performance-with-amazon-elasticache-for-redis/ Although the question just says "RDS Database", it doesn't specify what type of DB.

Elasticahe is NOSQL, A is the Answer!

Pretty sure answer is option B. You have to use a caching to 'reduce' database reads so read replica is out of option. The question mentions High availability so Redis is preferable than MemCached.

the question is clearly says reduce reads request, so b is the naswer

Use ElastiCache to reduce reading and ensure high availability. Opt A read replica its for performance not HA I will vote for B

the answer should be A, read replicas enhance high availability by providing failover capabilities in case the primary instance becomes unavailable.

AvsB A:Creating read replicas will ensure the availability of the DB. (CORRECT) B: Will reduce the reading and what happens when there is more reads.

A. Add Amazon RDS read replicas. Amazon RDS read replicas allow you to create one or more read-only copies of your RDS database instance. By offloading read traffic to read replicas, you can distribute the workload across multiple database instances, reducing the load on the primary database and decreasing the number of reads it needs to handle. This helps to improve the overall performance and scalability of your application.

B is right answer

https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ReadRepl.html "A read replica is a read-only copy of a DB instance. You can reduce the load on your primary DB instance by routing queries from your applications to the read replica."

A cannot be write as more read replicas doesn't reduce the number of database queries. A is correct as cached data reduces the number of database queries as content is served from cache instead.

B is incorrect because you have to explicitly enable and configure read replicas for Amazon ElastiCache for Redis. It's not enabled by default, and the choice says nothing about enabling read replicas for Elastichache for Redis. So B serves only the purpose of off-loading reads but not the HA one, while A will reduce the read requests for the main DB AND you can promote the read replica in case the main one fails, aka achieving high availability.

Benefits of Amazon RDS Read Replicas: Enhanced performance Increased availability Designed for security