Category: distributed-systems
Posts in this Category (4)
Convergence vs Consensus in Distributed Systems
Published on: October 20, 2025
Convergence and consensus are two closely-related properties of distributed systems implementing the replicated state machine (RSM) abstraction. While convergence requires replicas to eventually agree on the value of a decision variable, consensus requires them to never disagree. This subtle distinction makes all the difference in practice: while convergence can be...Dynamo and DynamoDB
Published on: September 20, 2016
In this post, I discuss DeCandia et al’s Dynamo paper, and Amazon’s DynamoDB service based on the paper. Dynamo DeCandia et al’s Dyanamo is a distributed key-value store remarkable for it’s entirely decentralized architecture, SLAs that focus on 99.9th percentile latency, emphasis on never losing writes, and the notorious sloppy...Notes - Terry's Session Guarantees
Published on: December 05, 2015
This post is the compilaton of my notes on Terry et al’s PDIS’94 paper: Session Guarantees for Weakly Consistent Replicated Data. System Model From what I understand, the paper is the first to describe the abstract system model of a weakly consistent replicated database that now serves as a frame...CAP Theorem and Related
Published on: September 09, 2014
My intention in writing this note is to understand the relation between conventional model of distributed systems that they usually teach in the distributed systems course and the the distributed web services hosting replicated datatypes. Fault tolerance is a concern in the former, and it is studied separately from communication...