The Backend Engineering Show with Hussein Nasser

Correction: Google is implementing the proposal originally submitted by researchers from Georgia institute of tech. I incorrectly said in the video that google is proposing this . Google is finally implementing a proposal from 2008 by researchers from Georgia institute of technology to make DNS cache poisoning . https://astrolavos.gatech.edu/articles/increased_dns_resistance.pdf https://datatracker.ietf.org/doc/html/draft-vixie-dnsext-dns0x20-00 0:00 Intro 2:00 How DNS Work 5:00 DNS Cache Poisoning 14:00 gOoGLe dot CoM 16:20 ASCII 0x20 casing 18:30 Randomizing the casing with encryption 22:30 limitations of this proposal 24:00 Credits

https://dropbox.tech/infrastructure/increasing-magic-pocket-write-throughput-by-removing-our-ssd-cache-disks In this episode of the backend engineering show I’ll discuss how Dropbox improved their write through put by 20% by removing all their SSDs (yes I was surprised too). DropBox uses an SSD layer as a write-back cache with SMR drives as their backend persistent storage. They changed their model to write directly to the hard drives. 0:00 Intro 2:00 Article Summary 3:00 SMR Drives 6:00 SSD Cache & WriteBack 8:00 Replacing Cache 9:30 Storage Engine Background 14:30 Why did they do it 15:00 The limitation of SSDs & Zoned Namespaces 19:30 Updating the Storage Engine 22:30 Tradeoffs 26:00 Rollout 28:00 Summary

The communication between backend applications and database systems always fascinated me. The protocols keep evolving and we are in constant search for an efficient protocol that best fit the workload of Backend-DB communication. In this episode of the backend engineering show I go through a blog written by  @PlanetScale  doing an experimentation of using HTTP/3 and HTTP/2 comparing it with MySQL Binary protocol. https://planetscale.com/blog/faster-mysql-with-http3 0:00 Intro 7:45 MySQL Binary vs HTTP 10:20 The Tests 15:00 Connection Cost + Select 1 22:00 Parallel Select 26:00 The cost of H2 and H3

Fundamentals of Database Engineering udemy course (link redirects to udemy with coupon) https://database.husseinnasser.com Shopify posted a blog on tips to for scalable payment system, one tip peeked my interest related to switching from UUID to ULID. I explore the reasoning behind this in this video. https://shopify.engineering/building-resilient-payment-systems 0:00 Intro 1:30 idempotency 6:30 UUID vs ULID 9:50 Clustered Index 13:30 Why UUID4 Inserts are slow 17:15 How ULID helps Shopify 22:00 Problem with tail pages 25:00 Does ULID help in all cases? Fundamentals of Backend Engineering Design patterns udemy course (link redirects to udemy with coupon) https://backend.husseinnasser.com

I’m a big believer that database systems share similar core fundamentals at their storage layer and understanding them allows one to compare different DBMS objectively. For example, How documents are stored in MongoDB is no different from how MySQL or PostgreSQL store rows. Everything goes to disk, the trick is to fetch what you need from disk efficiently with as fewer I/Os as possible, the rest is API.  In this video I discuss the evolution of MongoDB internal architecture on how documents are stored and retrieved focusing on the index storage representation. I assume the reader is well versed with fundamentals of database engineering such as indexes, B+Trees, data files, WAL etc, you may pick up my database course to learn the skills. Let us get started. Fundamentals of Backend Engineering Design patterns udemy course (link redirects to udemy with coupon) https://backend.husseinnasser.com Fundamentals of Networking for Effective Backends udemy course (link redirects to udemy with coupon) https://network.husseinnasser.com Fundamentals of Database Engineering udemy course (link redirects to udemy with coupon) https://database.husseinnasser.com

The User Interface/User Experience has great impact on the backend architecture and scalability. In this podcast I discuss three UI/UX that affected backend design and scalability. 0:00 Intro 1:40 UI vs UX 4:30 Google Chrome OmniBox 12:30 1 out of X Page 20:00 YouTube Notification Resources https://blog.apnic.net/2020/08/21/chromiums-impact-on-root-dns-traffic/ Fundamentals of Backend Engineering Design patterns udemy course (link redirects to udemy with coupon) https://backend.husseinnasser.com

In this video I explain how DHCP work and how it updates DNS entries for new hosts joining the network. I'll also mention Zero Config 0:00 Intro 1:00 the Network configuration 6:00 Showing DHCP in Wireshark 6:30 DHCP Discover 14:40 DHCP Offer 19:00 DHCP Request 21:30 DHCP ACK 22:00 How DHCP Updates DNS 26:15 Zero Configuration (mDNS, Link-local) Resources Dhcp https://datatracker.ietf.org/doc/html/rfc1541 Dynamic updates , dhcp RFC2136 https://datatracker.ietf.org/doc/html/rfc2136 https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr_dhcp/configuration/xe-3se/3850/dhcp-xe-3se-3850-book/dhcp-client-option-12.pdf RFC 1497 https://www.rfc-editor.org/rfc/rfc1497.html https://www.rfc-editor.org/rfc/rfc6762#ref-Zeroconf Link-local https://www.rfc-editor.org/rfc/rfc3927

Fundamentals of Backend Engineering Design patterns udemy course (link redirects to udemy with coupon) https://backend.husseinnasser.com Certificates provide a way to authenticate both the server and the client and are included as part of the TLS handshake. However, the certificates can be large because the full certificate chain is included in the handshake. The large certificates can go up to 10KB in size and take multiple segments to deliver and assemble. RFC 8879 discusses how TLS compression can be achieved, I discuss that in this podcast. Enjoy. 0:00 Intro 4:15 Certificate Chain 6:00 Faking the chain 8:50 Certificate Stores 10:30 Including ROOT cert in the chain 12:00 The performance penalty of large certificate chain 20:15 RFC 8879 TLS Certificate Compression 23:00 How Compression Works in TLS 1.2 vs TLS 1.3 30:30 What could go wrong? Resources https://datatracker.ietf.org/doc/rfc8879/ https://www.rfc-editor.org/rfc/rfc5246 https://www.rfc-editor.org/rfc/rfc6928.html

Two new vulnerabilities in openssl were discovered, we discuss them in this video https://www.openssl.org/news/secadv/20221101.txt

Google recent paper on protective load balancing in TCP attempts to improve packet drops and latency by making the host change the flow path using the IPv6 Flow label. The Linux kernels gets the PLB support in Linux 6.2 this December, let us discuss with this is.