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Memcached Support

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Memcached is another in-memory caching engine supported by Amazon ElastiCache. It is a high-performance, distributed object caching system designed to speed up dynamic web applications by lowering the number of times a database or API must be read. Memcached is simple, fast and memory-efficient. Am…

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AWS Certified Solutions Architect - Memcached Support Example Questions

Test your knowledge of Memcached Support

Question 1

Your application uses Amazon ElastiCache for Memcached to cache results of read‑heavy database queries. Users report increased latency. CloudWatch shows a cache hit ratio around 60%, consistently high evictions, node memory utilization above 90%, and no change in average item size or request pattern. Without changing application code, which action will most effectively increase the cache hit ratio?

Correct Answer: Increase the size of the cache cluster

The metrics indicate memory pressure: high and sustained evictions with node memory utilization over 90% and no change in item size or access pattern. In Memcached, frequent evictions remove hot keys before they can be reused, reducing hit ratio. Increasing the cache capacity (by adding nodes or using larger node types) lowers evictions, keeps hot items resident longer, and measurably improves the hit ratio. Decreasing TTL would shorten how long items remain cached and typically reduces the chance of reuse, further lowering hit ratio under these conditions. Decreasing the cluster size would exacerbate evictions. Enabling automatic backups does not address hit ratio and is not applicable to ElastiCache for Memcached.

Question 2

An application is using Amazon ElastiCache for Memcached with multiple nodes to improve responsiveness. Despite following best practices for node sizing, one node remains underutilized. What should you do to resolve the node underutilization issue?

Correct Answer: Implement key partitioning across nodes

Implementing key partitioning across nodes would distribute the cache read and write requests more evenly, resolving node underutilization. Switching to Redis or adjusting the size or number of Nodes aren't solution to the issue. Read replicas and key eviction settings are not relevant.

Question 3

You need to provide a high availability solution for the ElastiCache for Memcached deployment. How can you achieve this?

Correct Answer: Use ElastiCache with multiple nodes in different availability zones

Using multiple nodes in different availability zones will provide high availability. ElastiCache for Memcached does not support Multi-AZ deployment, read replicas, and automatic backups like Redis. Node size and connection timeout won't affect high availability.

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