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Geico·Software Engineer·Onsite - System Design / Architecture·Senior

Senior
Apr 2026

Summary

Geico software engineer interview focused on a high write-throughput system design problem. Pretty lean on details but the core challenge was real enough to keep me busy for a while.

Questions Asked (1)

Q1

Design a system that can handle extremely high write throughput at scale.

System DesignTechnical Trade-offs
Author's notes

Jumped straight into queuing and async writes, which felt right, but I spent too long on the ingestion layer and barely touched replication strategy before time ran out.

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AI HintsAI Generated

Suggested Approach

Start by clarifying requirements: expected write volume (e.g., writes per second), data size, latency tolerance, consistency needs, and durability guarantees. Then propose a scalable architecture that distributes writes across partitions, uses asynchronous processing, and optimizes storage for high write throughput, while discussing trade-offs like consistency vs. availability and cost.

Pro tip: Emphasize that high write throughput often requires decoupling ingestion from processing (e.g., via a log or queue) and that eventual consistency is usually acceptable for write-heavy systems. Also, mention the importance of monitoring and backpressure to handle bursts.

1. Clarify Requirements and Constraints

Ask about write volume, data size, latency, consistency, durability, and budget. This ensures the design meets actual needs and shows you avoid assumptions.

2. High-Level Architecture

Propose a distributed system with a write-optimized ingestion layer (e.g., API gateway, load balancer), a durable message queue or log (e.g., Kafka), and a partitioned storage layer (e.g., Cassandra, DynamoDB).

3. Partitioning and Scaling

Explain how data is partitioned (e.g., by key hash) to distribute writes evenly, and how to scale horizontally by adding nodes. Discuss replication for durability and availability.

4. Write Path Optimization

Detail techniques like batching, asynchronous writes, append-only logs, LSM trees, and in-memory buffers to maximize throughput. Mention trade-offs like increased latency or complexity.

5. Trade-offs and Failure Handling

Discuss consistency models (e.g., eventual consistency), durability guarantees, backpressure, and how to handle node failures, hot partitions, and data skew.

Key Points to Mention

  • Partitioning/sharding strategies (e.g., consistent hashing) to distribute write load
  • Use of append-only logs or LSM trees for high write throughput
  • Asynchronous processing and batching to reduce per-write overhead
  • Replication and durability guarantees (e.g., quorum writes)
  • Trade-offs between consistency, availability, and latency (CAP theorem)
  • Monitoring, backpressure, and auto-scaling to handle bursts

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.