Design a large-scale Caching Platform

Last updated: December 24, 2025

Quick Overview

Design a event-driven caching system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.

SentinelOne
System Design
Software Engineer
SentinelOne
December 24, 2025
Software Engineer
System Design Round
System Design
Medium

48

14

4,877 solved


Design a event-driven caching system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.

This is a common system design question asked during System Design Round at SentinelOne. The interviewer expects you to demonstrate your ability to design large-scale distributed systems, make well-reasoned trade-offs, and communicate your thought process clearly. SentinelOne values engineers who can think about scalability from day one.

What the Interviewer Expects
  • Systematically gather requirements and estimate capacity (QPS, storage, bandwidth)
  • Design a scalable architecture with clear component responsibilities
  • Make well-reasoned database and caching decisions with trade-off analysis
  • Address consistency vs availability trade-offs specific to the use case
  • Discuss partitioning strategy, replication, and data modeling
  • Cover failure handling, monitoring, and alerting strategies
Key Topics to Cover
Monitoring, logging, and alerting
API design and rate limiting
Consistency models and replication
Requirements gathering and capacity estimation
Load balancing and horizontal scaling
Database selection and data modeling
How to Approach This
  1. Start by clarifying functional and non-functional requirements with the interviewer.
  2. Estimate the scale: QPS, storage, bandwidth. This drives your design decisions.
  3. Draw a high-level architecture first, then deep dive into 1-2 critical components.
  4. Discuss trade-offs explicitly (e.g., consistency vs availability, SQL vs NoSQL).
  5. Address failure scenarios, monitoring, and how the system handles 10x traffic spikes.
Possible Follow-up Questions
  • How would you handle a region-wide outage?
  • How would you implement rate limiting to protect the system?
  • What happens if one of your database nodes goes down?
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Sample Answer
Requirements

Functional Requirements:

  1. Event-Driven Cache: The system should cache responses to events (e.g., API requests) and support event-based updates to the cache.
  2. High Throughput: The cachi...
Capacity Estimation

Back-of-Envelope Calculations:

  • Expected QPS: Assume 10 million requests per second at peak.
  • Cache Size: If each cached item is approximately 1 KB and we want to cache 100 million uniqu...

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