Cloudflare Reclaims 100 TB of RAM by Optimizing Consistent Hashing
InfoQ, Saturday, October 24th, 2026
Cloudflare cut more than 100 TB of memory by using probability analysis to drop 90% of hash points in its Rust consistent-hashing library.
Cloudflare documented how it cut the memory footprint of its internal load-balancing service by more than 100 TB by optimizing pingora-ketama, the Rust consistent-hashing implementation behind its Pingora Backend Router.
Statistical analysis showed diminishing returns from more hash points, with the final 90,000 hashes improving distribution error by only 0.7%, so engineers cut hashes per backend by about 90% while preserving accuracy.
The birthday paradox explained rising collisions among 32-bit hash points.
They also packed each ring entry from 8 bytes to 6 and rolled out the new ring gradually to avoid invalidating cached content across the network.