All distributed storage systems rely upon replication for durability and availability; but every system seems to have their own approach to replication: quorum replication, chain replication, primary/backup, Paxos/Raft and many others. This post is an attempt to understand the landscape of these algorithms through the lens of generating a unique sequence number. It was prompted by a question from a colleague who asked: how is it possible that Amazon Aurora can use simple quorum replication to achieve strong consistency? Doesn’t quorum replication provide only…

#distributed-systems #paxos #nosql #replication #database