Uber's Failover Architecture: Reconciling Reliability and Efficiency in Hyperscale Microservice Infrastructure
Abstract
Operating a global, real-time platform at Uber's scale requires infrastructure that is both resilient and cost-efficient. Historically, reliability was ensured through a costly 2x capacity model--each service provisioned to handle global traffic independently across two regions--leaving half the fleet idle. We present Uber's Failover Architecture (UFA), which replaces the uniform 2x model with a differentiated architecture aligned to business criticality. Critical services retain failover guarantees, while non-critical services opportunistically use failover buffer capacity reserved for critical services during steady state. During rare "full-peak" failovers, non-critical services are selectively preempted and rapidly restored, with differentiated Service-Level Agreements (SLAs) using on-demand capacity. Automated safeguards, including dependency analysis and regression gates, ensure critical services continue to function even while non-critical services are unavailable. The quantitative impact is significant: UFA reduces steady-state provisioning from 2x to 1.3x, raising utilization from ~20% to ~30% while sustaining 99.97% availability. To date, UFA has hardened over 4,000 unsafe dependencies, eliminated over one million CPU cores from a baseline of about four million cores.
Cite
@article{arxiv.2603.07345,
title = {Uber's Failover Architecture: Reconciling Reliability and Efficiency in Hyperscale Microservice Infrastructure},
author = {Mayank Bansal and Milind Chabbi and Kenneth Bogh and Srikanth Prodduturi and Kevin Xu and Amit Kumar and David Bell and Ranjib Dey and Yufei Ren and Sachin Sharma and Juan Marcano and Shriniket Kale and Subhav Pradhan and Ivan Beschastnikh and Miguel Covarrubias and Chien-Chih Liao and Sandeep Koushik Sheshadri and Wen Luo and Kai Song and Ashish Samant and Sahil Rihan and Nimish Sheth and Uday Kiran Medisetty},
journal= {arXiv preprint arXiv:2603.07345},
year = {2026}
}