SAP-C02 Practice Question 86: MemoryDB Durable Primary Redis API

AWS Certified Solutions Architect – Professional (SAP-C02) · Test 9 · question 6 of 10

Design for New Solutionshard

A gaming company stores player sessions and leaderboards in Redis sorted sets on a self-managed cluster, with a relational database kept in step for durability. The application code uses Redis commands and data structures extensively. The company wants a managed service that offers microsecond reads, that never loses acknowledged writes when a node fails or restarts, and that removes the need to run a separate durable database next to the in-memory data.

Which solution meets these requirements with the LEAST application change?

Show answer and explanation

Answer:

A. Migrate to Amazon MemoryDB and use it as the primary database

Amazon MemoryDB is *"a durable, in-memory database service"* that is *"compatible with the popular open source data stores Valkey and Redis OSS"*, so applications keep *"the same flexible and friendly data structures, APIs, and commands."* It provides *"microsecond read and single-digit millisecond write latency"* and *"stores data durably across multiple Availability Zones using a Multi-AZ transactional log to enable fast failover, database recovery, and node restarts."* AWS says it can be used *"as a high-performance primary database ... eliminating the need to separately manage both a cache and durable database"* (option A).

- B is wrong because ElastiCache is a cache. Data replicates asynchronously, so a failover can lose recently acknowledged writes, and the company would still need the relational database. - C is wrong because DynamoDB with DAX does not speak the Redis protocol, so the sorted-set logic must be rewritten, and DAX is still a separate cache in front of the table. - D is wrong because Aurora is not an in-memory store and does not provide sorted sets, so microsecond reads and the Redis commands would both be lost.

Reference: What is MemoryDB

Practice Test 9 ›

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