AWS Certified Database – Specialty — Question 263

A large financial services company uses Amazon ElastiCache for Redis for its new application that has a global user base. A database administrator must develop a caching solution that will be available across AWS Regions and include low-latency replication and failover capabilities for disaster recovery (DR). The company's security team requires the encryption of cross-Region data transfers.

Which solution meets these requirements with the LEAST amount of operational effort?

Answer options

• A. Enable cluster mode in ElastiCache for Redis. Then create multiple clusters across Regions and replicate the cache data by using AWS Database Migration Service (AWS DMS). Promote a cluster in the failover Region to handle production traffic when DR is required.
• B. Create a global datastore in ElastiCache for Redis. Then create replica clusters in two other Regions. Promote one of the replica clusters as primary when DR is required.
• C. Disable cluster mode in ElastiCache for Redis. Then create multiple replication groups across Regions and replicate the cache data by using AWS Database Migration Service (AWS DMS). Promote a replication group in the failover Region to primary when DR is required.
• D. Create a snapshot of ElastiCache for Redis in the primary Region and copy it to the failover Region. Use the snapshot to restore the cluster from the failover Region when DR is required.

Correct answer: B

Explanation

Amazon ElastiCache for Redis Global Datastore provides fully managed, secure, cross-Region replication with minimal latency, making Option B the solution with the least operational overhead. Utilizing AWS DMS to synchronize Redis clusters (Options A and C) introduces unnecessary complexity and is not a native or recommended approach for real-time Redis replication. Relying on cross-Region snapshot copies (Option D) fails to provide low-latency replication and results in high recovery times during a failover.