Efficient and Modular Consensus-Free Reconfiguration for Fault-Tolerant Storage

TL;DR

This paper introduces FreeStore, a modular, efficient, and consensus-free reconfiguration protocol for fault-tolerant storage systems that dynamically adapt to server set changes while maintaining consistency.

Contribution

It presents a novel reconfiguration protocol using view generators, enabling dynamic, consensus-free, and modular reconfiguration in fault-tolerant storage systems.

Findings

Reconfigurations are performed without consensus, improving efficiency.

The protocols support dynamic join/leave of servers during execution.

System performance is enhanced through modular design.

Abstract

Quorum systems are useful tools for implementing consistent and available storage in the presence of failures. These systems usually comprise a static set of servers that provide a fault-tolerant read/write register accessed by a set of clients. We consider a dynamic variant of these systems and propose FreeStore, a set of fault-tolerant protocols that emulates a register in dynamic asynchronous systems in which processes are able to join/leave the servers set during the execution. These protocols use a new abstraction called view generators, that captures the agreement requirements of reconfiguration and can be implemented in different system models with different properties. Particularly interesting, we present a reconfiguration protocol that is modular, efficient, consensus-free and loosely coupled with read/write protocols, improving the overall system performance.