Chapter 1: Introduction to Distributed Systems
Overview
Distributed systems are collections of independent computers that appear to users as a single coherent system. Understanding distributed systems is fundamental to grasping why CRDTs are necessary and how they solve critical problems.
Key Concepts
What is a Distributed System?
A distributed system consists of multiple autonomous computers that communicate through a computer network and coordinate their actions by passing messages to one another.
Challenges in Distributed Systems
- Network Partitions: Communication failures between nodes
- Node Failures: Individual nodes can crash or become unavailable
- Clock Synchronization: Different nodes may have different notions of time
- Concurrent Updates: Multiple nodes updating the same data simultaneously
- Consistency: Ensuring all nodes eventually see the same data
The CAP Theorem
The CAP theorem states that it's impossible for a distributed data store to simultaneously provide more than two out of three guarantees:
- Consistency (C): All nodes see the same data at the same time
- Availability (A): Every request receives a response
- Partition Tolerance (P): The system continues to operate despite network partitions
Why CRDTs Matter
CRDTs provide a way to achieve eventual consistency while maintaining high availability, making them ideal for distributed systems where immediate consistency can be sacrificed for better performance and fault tolerance.
Next Steps
In the next chapter, we'll explore different consistency models and how they relate to CRDTs.