What are the differences between Paxos and ZAB?

What are the differences between Paxos and ZAB?

Paxos and ZAB are both consensus algorithms, but they have different use cases and mechanisms. Paxos is more theoretical and is often used in distributed systems for achieving consensus in a fault-tolerant manner. ZAB, on the other hand, is specifically designed for ZooKeeper and is optimized for high throughput and low latency.

Can you explain how Paxos works?

Sure! Paxos works in several phases: the proposal phase, where a proposer suggests a value; the acceptance phase, where acceptors respond to proposals; and the learning phase, where learners are informed of the chosen value. It ensures that a majority of nodes agree on a single value, even in the presence of failures.

What about ZAB? How does it ensure consistency?

ZAB ensures consistency through a leader-follower model. The leader handles all write requests and replicates the changes to the followers. If the leader fails, a new leader is elected, ensuring that the system can continue to operate while maintaining consistency.

Which one is better for a distributed database?

It depends on your specific needs. If you require high availability and low latency, ZAB might be better, especially for systems like ZooKeeper. If you need a more general-purpose consensus algorithm that can handle various scenarios, Paxos could be the right choice.