Redesigning Workers KV for increased availability and faster performance

Cloudflare experienced a major service outage on June 12, 2025, due to a failure in the storage infrastructure of its Workers KV service, which was exacerbated by the outage of a third-party cloud provider. Workers KV, a global key-value store supporting high read volumes, initially relied on a dual-provider architecture to maximize availability. However, as usage increased, the system faced operational challenges, leading to a temporary reliance on a single provider. The outage highlighted the need for a more resilient architecture, prompting Cloudflare to transition to its own infrastructure using a hybrid storage approach that combines distributed databases and Cloudflare R2. This new setup races writes to both backends, ensuring durability and minimizing latency, while a sophisticated synchronization process maintains data consistency across providers. The implementation of KV Storage Proxy (KVSP) facilitates communication between Cloudflare Workers and database clusters, optimizing for the storage of small objects typical of Workers KV traffic. The refined architecture not only restores dual-provider capabilities but also significantly improves performance and availability, laying the groundwork for Cloudflare's complete infrastructure independence and enhancing the reliability of Workers KV for its users.