Cloudflare Cuts 100 TB of Memory from 1.1.1.1 DNS Cache

8 relevance

Cloudflare's Rust-based DNS cache redesign offers concrete memory optimization lessons.

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Why It Matters

For a platform engineer working on large-scale cloud infrastructure, this demonstrates how low-level memory layout optimizations in Rust can yield dramatic resource savings and performance wins even in established systems like DNS resolvers.

Key Takeaways

Apply compact memory representations (e.g., wire-format buffers, boxed slices, bitflags) to hot-path caches to reduce footprint and improve throughput without changing the underlying data model.

Cloudflare Cuts 100 TB of Memory from 1.1.1.1 DNS Cache

Summary

Cloudflare optimized its Big Pineapple DNS cache in Rust by reducing per-entry footprint from 953 to 420 bytes across five changes (Box<[T]>/Box<str>, bitflags, DNS wire format), freeing 100 TB fleetwide across over 250 billion entries. Insertion throughput increased 43% and lookup latency fell 19%, with p99 memory per instance dropping from 9.3 GB to 5.3 GB after a May-July 2026 rollout.

Author

Leela Kumili