An architecture for scaling performance and availability in global consensus systems

However, existing consensus algorithms treat these properties as fundamental trade-offs: scaling fault tolerance, adding servers, or geographic distribution inevitably degrades either performance or availability. This thesis identifies that this tradeoff stems from a core bottleneck in traditional Paxos and Flexible Paxos-based algorithms: the requirement for all agents to participate in all aspects of every agreement, called here global participation.<br><br>This thesis presents a systematic approach to removing global participation bottlenecks in consensus through Proposer Acceptor Mappings (PAMs), which partition consensus agents across different portions of the ledger.

First, to enable broad adoption of PAMs, this thesis presents PAM-based Paxos, an abstraction generalisation of existing Paxos algorithms that unifies Synod and Multi-Paxos constructions whilst enabling agent partitioning. Building on this foundation, three PAM designs are presented: the Geographic PAM, Horizontal PAM, and Conflict Minimising PAM. Each addresses specific scalability bottlenecks arising from global participation.