Which solution meets these requirements?
Create an Amazon ElastiCache cluster. Use a write-through strategy to populate the cache.
Create an Amazon ElastiCache cluster. Use a lazy loading strategy to populate the cache.
Change the DB instance to Multi-AZ with a standby instance in another AWS Region.
Create a read replica of the DB instance. Use the read replica to distribute the read traffic.
Explanations:
While creating an Amazon ElastiCache cluster with a write-through strategy could improve performance, it is generally more suitable for scenarios with frequent updates and repeated queries. In this case, the database is read-intensive with very few repeated queries, making this option less optimal.
A lazy loading strategy in Amazon ElastiCache is effective for caching frequently accessed data, but it may introduce latency during cache misses, which can be detrimental for read-intensive workloads with few repeated queries. This option does not directly address the need for distributing read traffic efficiently.
Changing the DB instance to Multi-AZ improves availability and disaster recovery but does not enhance read scalability. Multi-AZ is designed for failover rather than load distribution, making it unsuitable for handling increased read traffic.
Creating a read replica allows the distribution of read traffic across multiple instances, effectively handling the read-intensive workload. This option is specifically designed to offload read queries from the primary database instance, improving performance and scalability.
I suspect that the answer is:
Create a read replica of the DB instance. Use the read replica to distribute the read traffic.