What is the Bulkhead Pattern in System Design?
Bulkhead pattern is a resilience design strategy that isolates parts of a system into separate compartments so if one fails, the others keep running.
When to use/Use Cases
Apply the Bulkhead pattern in microservices or distributed systems where one overloaded service shouldn’t bring everything down. It’s common in APIs, payment systems, or apps that need graceful degradation—ensuring critical services stay responsive even if non-critical ones fail.
Example
A web app uses separate thread pools: one for user requests and another for background tasks. If emails stall, users can still browse without issues.
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Why Is It Important
Bulkheads improve reliability by preventing a single point of failure from cascading across services. They ensure high availability and protect user experience.
Interview Tips
Explain the ship bulkhead analogy, give a real-world example (like DB connections per service), and contrast it with a circuit breaker. Highlight that bulkheads isolate failure impact, while circuit breakers stop bad calls.
Trade-offs
You gain fault isolation and resilience but trade off efficiency. Partitioned resources can lead to idle capacity and extra management overhead.
Pitfalls
Common errors include over-isolating (too many bulkheads wasting resources) or under-isolating (not enough protection). Bulkheads should complement, not replace, patterns like circuit breakers and rate limiting.
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