Q26 — AWS SAA-C03 Ch.17

Question 26 of 89 | ← Chapter 17

Q1326. A database is on an Amazon RDS MySQL 5.6 Multi-AZ DB instance that experiences highly dynamic reads. Application developers notice a significant slowdown when testing read performance from a secondary AWS Region. The developers want a solution that provides less than 1 second of read replication latency.What should the solutions architect recommend?

Correct Answer: B. Migrate the database to Amazon Aurora with cross-Region replicas.

Explanation

To achieve less than 1 second of read replication latency for a highly dynamic read workload in a secondary AWS Region, the best solution is:Correct Answer:B. Migrate the database to Amazon Aurora with cross-Region replicas.Why Amazon Aurora with Cross-Region Replicas is the Best Choice?\1. Aurora Provides Low-Latency Cross-Region ReplicationAmazon Aurora is a high-performance MySQL/PostgreSQL-compatible database designed for low-latency replication.Cross-Region Aurora replicas typically have sub-second replication lag, making them ideal for active read workloads in a secondary Region.Unlike RDS MySQL Multi-AZ (which is for failover, not read scaling) or RDS read replicas (which can have higher latency), Aurora replicas are optimized for performance.\2. Better Than RDS MySQL Read Replicas (Option C)RDS MySQL read replicas (even cross-Region) can suffer from higher replication lag (often several seconds) due to:Asynchronous replication (vs. Aurora's optimized sync mechanism).Network latency between Regions.Aurora's replication protocol is more efficient, reducing lag significantly.\3. Better Than EC2 MySQL (Option A)Running MySQL on EC2 requires manual setup, patching, and scaling, increasing operational overhead. Replication lag may still be high unless using a solution like Galera Cluster, which adds complexity. Aurora is fully managed, reducing maintenance efforts while providing better performance.4. ElastiCache (Option D) Does Not Solve Replication Latency Amazon ElastiCache (Redis/Memcached) is a caching layer, not a database replication solution. Use case: Improving read performance by caching frequently accessed data, but does not reduce replication lag between Regions.Not suitable if the application requires fresh data from the primary database.Comparison of OptionsOptionReplication LatencyManagement OverheadBest ForA. EC2 MySQLHigh (unless using Galera)High (manual setup)Custom MySQL deployments B. Aurora Cross-Region ReplicaSub-second (best)Low (managed)Active read scaling across Regions C. RDS MySQL Read ReplicaHigh (several seconds)Medium (managed)Passive read scaling D. ElastiCacheN/A (caching only)MediumSpeeding up read-heavy workloads Recommended ArchitectureMigrate the RDS MySQL database to Amazon Aurora MySQL.Set up a cross-Region Aurora replica in the secondary AWS Region. Configure read endpoints to distribute reads between the primary and replica(s).Monitor replication lag to ensure it stays below 1 second.ConclusionThe best solution for low-latency (<1s) read replication in a secondary Region is:B. Migrate the database to Amazon Aurora with cross-Region replicas.Other options either introduce high latency (C), require manual management (A), or do not address replication lag (D).