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/
Mentioned Videos
Cloudflare blog
https://blog.cloudflare.com/instant-purge/
Percentile Tail Latency Explained (95%, 99%) Monitor Backend performance with this metric
https://www.youtube.com/watch?v=3JdQOExKtUY
How Discord Stores Trillions of Messages | Deep Dive
https://www.youtube.com/watch?v=xynXjChKkJc
Fundamentals of Operating Systems Course
https://os.husseinnasser.com
Backend Troubleshooting Course
https://performance.husseinnasser.com
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1:02:21
Running out of TCP ephemeral source ports
In this episode of the backend engineering show I describe an interesting bug I ran into where the web server ran out of ephemeral ports causing the system to halt.
0:00 Intro
0:30 System architecture
2:20 The behavior of the bug
4:00 Backend Troubleshooting
7:00 The cause
15:30 Ephemeral ports on loopback
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20:06
Database Torn pages
0:00 Intro
2:00 File System Block vs Database Pages
4:00 Torn pages or partial page
7:40 How Oracle Solves torn pages
8:40 MySQL InnoDB Doublewrite buffer
10:45 Postgres Full page writes
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15:33
Cloudflare Open sources Pingora (NGINX replacement)
Get my backend course https://backend.win
Cloudflare has announced they are opening sources Pingora as a networking framework! Big news, let us discuss
0:00 Intro
0:30 Reasons why Cloudflare built Pingora?
3:00 It is a framework!
7:30 What in Pingora?
11:50 Security in Pingora
13:45 Multi-threading in Pingora
21:00 Customization vs Configuration
25:00 Summary
https://blog.cloudflare.com/pingora-open-source/?utm_campaign=cf_blog&utm_content=20240228&utm_medium=organic_social&utm_source=twitter
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31:05
Encrypted Client Hello - The Pros & Cons
The Encrypted Client Hello or ECH is a new RFC that encrypts the TLS client hello to hide sensitive information like the SNI. In this video I go through pros and cons of this new rfc.
0:00 Intro
2:00 SNI
4:00 Client Hello
8:40 Encrypted Client Hello
11:30 Inner Client Hello Encryption
18:00 Client-Facing Outer SNI
21:20 Decrypting Inner Client Hello
23:30 Disadvantages
26:00 Censorship vs Privacy ECH
https://blog.cloudflare.com/announcing-encrypted-client-hello/
https://chromestatus.com/feature/6196703843581952
About The Backend Engineering Show with Hussein Nasser
Welcome to the Backend Engineering Show podcast with your host Hussein Nasser. If you like software engineering you’ve come to the right place. I discuss all sorts of software engineering technologies and news with specific focus on the backend. All opinions are my own.
Most of my content in the podcast is an audio version of videos I post on my youtube channel here http://www.youtube.com/c/HusseinNasser-software-engineering
Buy me a coffee
https://www.buymeacoffee.com/hnasr
🧑🏫 Courses I Teach
https://husseinnasser.com/courses
Canada - english