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How Cloudflare achieved massive memory efficiency in their public DNS resolver

Saving 100 terabytes of memory by optimizing 1.1.1.1's DNS cache

Cloudflare Engineering

2024

02

The Challenge

Understanding the scale of memory consumption in a global DNS resolver

100+ TB
Memory consumed by 1.1.1.1 DNS cache infrastructure
Across Cloudflare's global network of data centers

Why DNS cache memory matters

  • 01
    Scale of operations 1.1.1.1 serves billions of DNS queries daily across 300+ global locations
  • 02
    Memory overhead Each cached DNS record consumed more memory than necessary
  • 03
    Infrastructure cost Excess memory usage increased operational costs and hardware requirements
  • 04
    Performance impact Memory inefficiency limited cache capacity and hit rates
05

The Solution

Engineering optimizations that delivered dramatic results

Key Optimization Techniques

compress

Data Structure Redesign

Replaced inefficient structures with memory-optimized alternatives

memory

String Interning

Eliminated duplicate domain names by sharing common strings

hub

Pointer Compression

Reduced pointer size from 8 bytes to 4 bytes where possible

settings_suggest

Cache Eviction Policy

Improved algorithms to remove stale entries more efficiently

Key Insights & Results

  • 01
    100TB memory savings Dramatic reduction in memory consumption across all data centers
  • 02
    Improved cache efficiency Same performance with significantly reduced resource footprint
  • 03
    Cost reduction Lower infrastructure costs enable more cache capacity at same budget
  • 04
    Open knowledge sharing Technical blog post shared learnings with the engineering community

Thank You

Optimization is not just about speed — it's about efficiency at scale

https://blog.cloudflare.com/dns-cache-memory-optimization-1111/
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