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

SeniorPrefer not to say
May 2026

Summary

LinkedIn system design round for a software engineer role, one big open-ended question about building a metrics monitoring platform from scratch. Felt like a lot of ground to cover in one session, but the structure helped keep things moving.

Questions Asked (1)

Q1

Design a metrics monitoring system that ingests time-series data from a large fleet of services and supports real-time querying, alerting, and dashboards. Walk through functional requirements, non-functional requirements, architecture, storage strategy, alert evaluation, and scaling trade-offs.

System DesignTechnical Trade-offsData Modeling
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AI HintsAI Generated

Suggested Approach

Start by clarifying functional and non-functional requirements, then propose a high-level architecture that separates ingestion, storage, query, and alerting. Dive into storage strategy (e.g., time-series database, downsampling) and alert evaluation (e.g., stream processing vs. periodic queries), highlighting trade-offs in scalability, latency, and cost.

Pro tip: Emphasize the importance of cardinality control and downsampling to handle high-volume metrics efficiently, and discuss how you'd design for multi-tenancy and fault tolerance—key concerns at LinkedIn's scale.

1. Clarify Requirements

Ask questions to understand scale (number of services, metrics per second, retention), query patterns (real-time vs. historical), alerting needs (latency, thresholds), and dashboard requirements.

2. High-Level Architecture

Outline components: ingestion (collectors, message queue), storage (time-series DB), query service, alert evaluator, and dashboard. Explain data flow from services to storage and query.

3. Storage Strategy

Choose a time-series database (e.g., Prometheus, InfluxDB, or custom). Discuss data model (metric name, tags, timestamp, value), retention policies, downsampling, and partitioning for scalability.

4. Alert Evaluation

Describe alert rule management, evaluation engine (streaming vs. batch), and notification. Discuss how to handle high cardinality and avoid alert storms.

5. Scaling Trade-offs

Discuss scaling ingestion (horizontal partitioning, sharding), query (caching, pre-aggregation), and alerting (distributed evaluation). Trade-offs: consistency vs. availability, latency vs. cost, and complexity vs. maintainability.

Key Points to Mention

  • Time-series data model and indexing (e.g., tags, time-based partitioning)
  • Ingestion pipeline with backpressure handling and exactly-once semantics
  • Downsampling and retention policies to manage storage costs
  • Alert evaluation strategies: streaming (e.g., Flink) vs. periodic queries
  • Query optimization: caching, pre-aggregation, and push-down filters
  • Multi-tenancy and isolation for different teams/services

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