Augmenting Flexible Paxos in LogDevice to improve read availability

What this post added

This post details improvements to LogDevice, Meta's scalable distributed log storage system, by augmenting its Flexible Paxos consensus algorithm to enhance read availability. It addresses the trade-offs in Flexible Paxos concerning read and write availability, particularly in the context of failures and maintenance. The post explains how LogDevice's recovery process and a separate membership mechanism using ZooKeeper were adapted to maintain write availability while improving read availability, even in scenarios where a majority of acceptors are unavailable, by allowing reads without a strict quorum and addressing 'stuck recovery' issues.