Cloudflare built a global cache purge system that runs under 150 ms.
This is how they did it.
Using RockDB to maintain local CDN cache, and a peer-to-peer data center distributed system and clever engineering, they went from 1.5 second purge, down to 150 ms.
However, this isn’t full picture, because that 150 ms is just actually the P50. In this video I explore Clouldflare CDN work, how the old core-based centralized quicksilver, lazy purge work compared to the new coreless, decentralized active purge. In it I explore the pros and cons of both systems and give you my thoughts of this system.
0:00 Intro
4:25 From Core Base Lazy Purge to Coreless Active
12:50 CDN Basics
16:00 TTL Freshness
17:50 Purge
20:00 Core-Based Purge
24:00 Flexible Purges
26:36 Lazy Purge
30:00 Old Purge System Limitations
36:00 Coreless / Active Purge
39:00 LSM vs BTree
45:30 LSM Performance issues
48:00 How Active Purge Works
50:30 My thoughts about the new system
58:30 Summary
Cloudflare blog
https://blog.cloudflare.com/instant-purge/
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Cloudflare blog
https://blog.cloudflare.com/instant-purge/
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