GoKawiilCloudflare shrinks 1.1.1.1 DNS cache entries to reclaim 100TB of RAM
Cloudflare redesigned how DNS cache entries are stored in memory for its 1.1.1.1 resolver platform, Big Pineapple, cutting each entry's size from 953 bytes to 420 bytes. The changes, detailed by systems engineer Sebastiaan Neuteboom, involved five Rust-level optimizations including fixed-size data structures, merged record lists, and raw wire-format storage instead of padded fields.
GoKawiil's interpretation of the reporting above, not reported fact.
With over 250 billion entries cached at once, even a single wasted byte per entry translates into roughly 250GB of lost memory across Cloudflare's fleet, so the redesign avoided costly hardware upgrades amid rising DDR5 prices. The optimization also boosted performance, raising insert throughput by 43% and cutting lookup latency by 19%, showing how software efficiency can rival physical infrastructure expansion.
- Cloudflare freed about 100TB of RAM fleet-wide without adding new hardware.
- Five Rust-based memory optimizations cut each DNS cache entry from 953 to 420 bytes.
- The changes also improved performance, increasing insert throughput and reducing lookup latency.
Programming Rust, 2nd Edition (O'Reilly) — Cloudflare's 100TB savings came from Rust-level tricks like swapping Vec and String for fixed-size boxed slices — exactly the kind of memory-layout thinking this book digs into. It's a thorough guide to ownership, allocation and data structures for anyone who wants to understand how those bytes add up.
See Programming Rust, 2nd Edition (O'Reilly) on Amazon → Affiliate link — we may earn a commission on purchases, at no extra cost to you. Product picked by AI based on this article; it is not a tested recommendation.Source: tomshardware.com — Luke James, 2026-08-28
Published there as: “Cloudflare frees up 100TB of RAM by shrinking 1.1.1.1's DNS cache entries — 250 billion cached DNS entries at any given time means one wasted byte costs 250GB”
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