Cloudflare rebuilds less DNS data and cuts peak memory by 85%

Cloudflare reports reducing peak Zone Builder memory from 79 to 12 GiB by rebuilding affected DNS data and combining queued changes for the same zone. That headroom enabled shorter safety waits, roughly halving build completion delay. The measured delay ends when data reaches its configuration store; it excludes distribution across the network and DNS query latency.

Cloudflare · Alex Fattouche · Nov 2, 2026

Why it matters

Incremental work pays off when the system can prove which outputs a change affects.

More context

The planner classifies changes, reads fresh database state before writing, and retains Kafka acknowledgments until work completes. Cloudflare compared targeted output with full builds and a separate mirror environment. Unknown changes generally retain full rebuilds, with an explicit operational exception for oversized zones.

Keep in mind

These are Cloudflare’s measurements and rollout conditions. The planner needs correct dependency information; the results do not promise equivalent savings for another pipeline.

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