James Mickens, a researcher in the Distributed Systems group at Microsoft Research, articulated a profound sense of weariness regarding the proliferation of academic work on Byzantine fault tolerance (BFT). According to his 2013 commentary published via USENIX, the pursuit of absolute reliability through complex protocols often overlooks the mundane, yet devastating, realities of system operation.
BFT protocols, designed to ensure consensus even when components fail maliciously, typically necessitate diagrams illustrating an explosion of message traffic to achieve theoretical correctness. Mickens contends that these diagrams, often presented as proof of superiority over prior work, represent an impractical overhead, suggesting that achieving consensus requires an astronomical number of messages.
He further noted that BFT papers frequently introduce novel, nearly inscrutable data consistency models, such as “leap year triple-writer dirty-mirror asynchronous semi-consistency.” Such terminology, while precise in theory, lacks intuitive grounding in real-world engineering experiences, making practical adoption difficult for operators.
To illustrate this disconnect, Mickens provided an analogy where a simple request to go to lunch devolves into a Byzantine state machine involving multiple verifications, accusations of faultiness, and counter-accusations among colleagues.
This thought experiment highlights the gap between formal verification and the operational environment, where human factors are often the most significant source of unreliability. The researcher points out that even the most robust protocol cannot safeguard against an operator like 'Ted the Poorly Paid Datacenter Operator' spilling coffee or mismanaging backups.
Ultimately, Mickens suggests that the academic focus on BFT represents an addiction to formalism that does not translate to the availability figures seen in production systems like Twitter. He implies that resources might be better spent addressing the predictable, non-malicious failures inherent in large-scale infrastructure.
This critique serves as a necessary counterpoint to purely theoretical advancements in distributed computing, urging practitioners to weigh the cost of cryptographic complexity against the practical impact of human fallibility in maintaining uptime.
