How We Saved 100 Terabytes of Memory by Optimizing 1.1.1.1's DNS Cache
Cloudflare, Thursday, August 27th, 2026
Five Rust-level cache layout optimizations cut per-entry memory 56%, freeing roughly 100 TB across Cloudflare's fleet.
Big Pineapple, the platform behind 1.1.1.1, Gateway DNS, DNS Firewall, AS112 and several other Cloudflare DNS services, holds over 250 billion DNS cache entries at any given time.
At that scale, wasting a single byte per entry costs more than 250 gigabytes of memory across the fleet, which turns micro-optimization into a fleet-level capacity question.
The post details five successive Rust-level changes to how cache entries are laid out in memory, together cutting per-entry memory use by 56%. The aggregate saving is approximately 100 terabytes of memory across Cloudflare's infrastructure.