From Static Rate Limiting to Adaptive Traffic Management in Airbnb’s Key-Value Store

How Airbnb hardened Mussel, our key-value store, with smarter traffic controls to stay fast and reliable during traffic spikes. By Shravan Gaonkar , Casey Getz , Wonhee Cho Introduction Every request lookup on Airbnb, from stays, experiences, and services search to customer support inquiries ultimately hits Mussel , our multi-tenant key-value store for derived data. Mussel operates as a proxy service, deployed as a fleet of stateless dispatchers — each a Kubernetes pod. On a typical day, this fleet handles millions of predictable point and range reads. During peak events, however, it must absorb several-fold higher volume, terabyte-scale bulk uploads, and sudden bursts from automated bots or DDoS attacks. Its ability to reliably serve this volatile mix of traffic is therefore critical to both the Airbnb user experience and the stability of the many services that power our platform. Given Mussel’s traffic volume and its role in core Airbnb flows, quality of service (QoS) is one of the p