Free AWS DVA-C01 Actual Exam Questions - Question 14 Discussion
application must be fault tolerant, natively highly scalable, and any service interruption should not
affect the user experience.
What is the best option to store the session state?
A/D? While stickiness (D) keeps things simple by tying users to one server, it’s risky if that server goes down, causing session loss. ElastiCache (A) offers distributed, in-memory storage that’s fast and scales well with zero downtime impact, which is vital for a smooth user experience. CloudFront (B) isn’t meant for session storage, and S3 (C) is too slow for real-time session needs. So between A and D, A fits better for fault tolerance and scalability without interrupting users.
A/C? S3 is super durable but too slow for session data. ElastiCache is fast and supports fault tolerance, which fits the need for no user impact during interruptions better.
It’s D since stickiness avoids syncing issues and keeps sessions consistent per user.
A/D? I get why A is popular since ElastiCache is fast and handles failover well, but D’s session stickiness keeps the user tied to one instance, so no constant session sync needed. The problem is if that instance fails, the session breaks. So D isn’t fully fault tolerant. A still seems more robust because it shares session state across all instances, making it scalable and fault tolerant. Stickiness might be simpler but won’t handle server failures smoothly.
It’s A because ElastiCache offers low-latency, in-memory storage that’s perfect for session state and supports automatic failover, unlike session stickiness which can cause issues if a server goes down.
It’s D because session stickiness lets users keep the same backend server during their session, so no need to constantly sync session data across instances. This avoids state-sharing complexity and helps with fault tolerance since the load balancer handles routing. ElastiCache is good but adds extra overhead and possible latency, while stickiness is simpler and often enough for many web apps.
It’s A, ElastiCache fits best for session state caching.