Designing Data-Intensive Applications – Single Leader Replication

We dive back into Designing Data-Intensive Applications to learn more about replication while Michael thinks cluster is a three syllable word, Allen doesn’t understand how we roll, and Joe isn’t even paying attention.

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In this episode, we are discussing Data Replication, from chapter 5 of “Designing Data-Intensive Applications”.

Replication in Distributed Systems

• When we talk about replication, we are talking about keeping copies of the same data on multiple machines connected by a network
• For this episode, we’re talking about data small enough that it can fit on a single machine
• Why would you want to replicate data?
  • Keeping data close to where it’s used
  • Increase availability
  • Increase throughput by allowing more access to the data
• Data that doesn’t change is easy, you just copy it
• 3 popular algorithms
  • Single Leader
  • Multi-Leader
  • Leaderless
• Well established (1970’s!) algorithms for dealing with syncing data, but a lot data applications haven’t needed replication so the practical applications are still evolving
  • Cluster group of computers that make up our data system
  • Node each computer in the cluster (whether it has data or not)
  • Replica each node that has a copy of the database
• Every write to the database needs to b