Consistency Patterns in Distributed Systems

Mastering System Design Interview Concepts

In the realm of distributed systems, consistency is a cornerstone topic. As systems grow and become more distributed across multiple nodes or even geographical locations, ensuring that they operate in a predictable manner becomes paramount. One of the most significant challenges in distributed systems is ensuring that the data remains consistent across all nodes. To tackle this, several consistency patterns have been developed. In this article, we’ll explore three of them: weak consistency, eventual consistency, and strong consistency.

Weak Consistency

Definition: Weak consistency guarantees that if no new updates are made to a particular item, eventually all accesses will return the last updated value.

Characteristics:

• No immediate synchronization: The system doesn’t guarantee that an update will be immediately seen by other nodes. This means that some nodes might see an old value even after the value has been updated elsewhere.
• Fast operations: Because it doesn’t have to wait for synchronization across all nodes, operations (like read and write) can be faster in systems with weak consistency.
• Higher availability: Weak consistency…