Exam AWS Certified Database - Specialty topic 1 question 319 discussion

C B and D would require application change.

https://aws.amazon.com/blogs/database/building-resilient-applications-with-amazon-documentdb-with-mongodb-compatibility-part-2-exception-handling/#:~:text=Amazon%20DocumentDB%20can%20scale%20reads%20by%20adding%20read,primary%20if%20all%20replicas%20are%20unavailable%20Weitere%20Elemente

C. Add one read replica instance. Set the read preference to secondary preferred. --- below copy / paste from mongodb web link --- By default, an application directs its read operations to the primary member in a replica set (i.e. read preference mode "primary"). But, clients can specify a read preference to send read operations to secondaries. https://www.mongodb.com/docs/manual/core/read-preference/

A: No. DDB uses a shared cluster volume by default. Adding 2 instances without setting which one is primary and read replica won't be most efficient for the load. B: No. DDB uses a shared cluster volume by default, no need to activate. Routing all read queries to a read replicas required application logic change, so No. C: Yes. Setting the read preference to "secondary preferred" means that read operations will be routed to read replicas when they're available. If not, they'll go to the primary. This change doesn't require any changes in the application logic, so it doesn't introduce application overhead. D: No. Required application change for read-write operation. https://docs.aws.amazon.com/documentdb/latest/developerguide/storage.html https://docs.aws.amazon.com/documentdb/latest/developerguide/db-cluster-read-preference.html

Amazon DocumentDB already has a cluster volume where data is shared across instances. So Answer is D. Any thoughts on this ?

In this solution, a read replica instance is added and the shared cluster volume is activated. This allows read queries to be distributed to the read replica instance, improving performance. At the same time, write queries are processed on the primary instance. This architecture scales the processing of read requests and can handle the anticipated increase in write requests. Additionally, since there is no need to modify the application, there is no added overhead. Therefore, solution B fulfills the requirements.