When we’re enjoying our favorite movie on a vast streaming service or tracking our travel itinerary real-time, we’re taking advantage of something called Network Replication. Imagine if a popular streaming service like Netflix had only one server and it crashed during the climactic scene of your favorite blockbuster. You'd be stuck waiting, wouldn't you?! In reality, Netflix stores multiple copies of this movie data across several servers in various locations. This concept is known as 'Network Replication.'

In layman's terms, Network Replication means creating and managing multiple ‘copies’ or replicas of data across different nodes (servers) in a distributed network. This methodology ensures high data availability, fault-tolerance, and improved access speed.

However, while this improves system performance, it also creates a unique challenge: how to keep these multiple replicas consistents even when they are updated independently and simultaneously (like those multi-million-dollar budget editors in their locked rooms doing updates). This is a standard problem in distributed systems known as the 'Replica Consistency Problem.'

Recalling those fraught finance folks, they could unknowingly create inconsistencies across other copies if their updates happened simultaneously and were propagated in different orders.

This problem can be solved using Conflict-free Replicated Data Types (CRDTs), which essentially offer a mathematical framework for achieving strong eventual consistency (SEC) in distributed systems without making the participants wait for each other. We'll take a deeper look into this in the coming sections.

xxxxxxxxxx

if __name__ == "__main__":

  # Python representation of distributed system

  distributed_system = ['Server 1', 'Server 2', 'Server 3']

​

  # each server stores a replica of the same data

  databases = {

    server: {'data': 'Blockbuster Movie'} for server in distributed_system

  }

​

  print('Initial state:', databases)

​

  # update on Server 1

  databases['Server 1']['data'] = 'Updated Scene'

​

  print('After update:', databases)