---
title: "Circuit Breakers"
description: "1 posts about Circuit Breakers, summarised, each linking to the original."
---

# Circuit Breakers
> 1 posts about Circuit Breakers, summarised, each linking to the original.

## Articles

### [Your Circuit Breaker is Misconfigured](https://yomu.fyi/post/your-circuit-breaker-is-misconfigured.md)
- Company: [Shopify](https://yomu.fyi/company/shopify.md)
- Author: 2023-10-18
- Published: Feb 18, 2020

Misconfigured circuit breakers can leave an application effectively unavailable during a dependency outage by allowing timed-out requests to consume worker capacity. Using Shopify’s Semian implementation, the post explains how name, error\_threshold, error\_timeout, half\_open\_resource\_timeout, and success\_threshold govern circuit opening, recovery, and wasted utilization across failing service instances. It models timeout spikes for a single worker, notes that separate names isolate services and instances, and presents an equation for steady-state additional utilization, while noting that context-switch costs are not included. A live test closely matched the equation’s prediction. In a Rails worker with two threads and 42 Redis instances, changing half\_open\_resource\_timeout from 0.25 seconds to 50ms and error\_timeout from 2 to 30 seconds reduced modeled extra utilization from 263% to 4%, with slower recovery; an author’s edit says success\_threshold does not affect steady-state utilization.