ElastiCache is managed in-memory caching — Redis or Memcached — that sits in front of your database to serve frequently-requested data in microseconds. It’s how you take read pressure off a database and speed up an app.
When the exam wants ElastiCache
The tell is “reduce database load” or “improve read latency for frequently-accessed data.” Redis adds persistence, replication, and more data structures; Memcached is simpler and purely for caching. If the scenario needs failover or advanced features, that’s Redis.
Test yourself
A read-heavy web app repeatedly queries the same data, straining the database. You want microsecond reads and less DB load. What do you add?
- A larger RDS instance
- Amazon ElastiCache in front of the database
- More EBS volumes
- A second Internet Gateway
👉 Click to reveal the answer & explanation
Correct answer: B. ElastiCache caches frequently-requested data in memory, cutting latency to microseconds and offloading the database. A bigger instance (A) is costlier and doesn’t cache; storage (C) and networking (D) don’t address repeated reads.
Related topics
Amazon RDS · Amazon Aurora · Amazon DynamoDB
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