What is an eventual consistency model and how does it apply to distributed systems?

Short answer: Eventual consistency is a consistency model used in distributed systems where updates to data will propagate and eventually become consistent across all nodes, but not necessarily immediately.

Explain a bit more

How it works: In an eventually consistent system, updates are made to a node and eventually, that update will be propagated to all other nodes. It allows for temporary inconsistencies, but ensures that the system will converge to a consistent state over time. Use cases: Suitable for systems that can tolerate a delay in consistency, like NoSQL databases (Cassandra, DynamoDB) and systems dealing with high availability and massive scale.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.