WhatsApp Went down again, this is an early report with brief analysis, enjoy. https://engineering.fb.com/2020/10/21/networking-traffic/how-facebook-is-bringing-quic-to-billions/
DNS or Domain Name System, despite its drawbacks, is brilliantly designed for scale. We can learn few lessons from this protocol especially when designing our own apps. This episode of the backend engineering show I go through how DNS works, the pros and the cons and attacks that happened on this system. 0:00 Intro 2:00 Overview DNS 7:40 How DNS works (Details) 15:44 DNS uses UDP 19:30 DNS Poisoning 24:10 is DNS really distributed? 26:30 How Attackers Abuse DNS 30:30 How Chrome overloaded the RO...
In this episode of the backend engineering show we discuss the Internet Protocol. A beautiful, elegant protocol that made the Internet possible. We discuss why we need an IP address, how routing is done and how VPNs take advantage of the agnostic nature to encrypt traffic
In this episode of the backend engineering show we discuss an article written by the Forem team illustarting a bug they recently fixed in their caching layers. They go into good level of details explaining the 3 levels of caching that they have. I go through this article in this episode and give my opinion at the end as to why we shouldn’t really cache unless we need to. Enjoy 0:00 Intro 1:00 Three level of caching summary 7:39 Edge Caching 8:30 Backend Rails Caching 10:30 Database Caching 15:00...
Backend database applications relay on good storage systems for performance, durability and low latency. SSDs have been a great invention that changed the storage game compared to mechanical drives. However, SSDs came with their own sets of problems which can cause database reads and writes to plummet after a while. This episode discusses the current limitations of SSDs include garbage collection, wear leveling, over provisioning and how zoned name spaces “may” fix this. 0:00 Intro 1:40 Block 4:...
Google linux boxes have over 16 NVMe SSD PCIe Express drives.When a shutdown signal is sent to linux, the OS iterate through each NVMe and send synchronous request to shutdown that takes 4.5 seconds. This adds up to over a minute to achieve a reboot. Google patches linux with asynchronous Shutdown APIs Resources https://www.phoronix.com/forums/forum/phoronix/latest-phoronix-articles/1316262-google-has-a-problem-with-linux-server-reboots-too-slow-due-to-too-many-nvme-drives patch https://lore.ker...
Hash tables are effective for caching, database joins, sets to check if something is in a list and even load balancing, partitioning and sharding and many other applications. Most programming languages support hash tables. However they don’t come without their cost and limitations lets discuss this. 0:00 Intro 1:50 Arrays 3:50 CPU Cost (NUMA/M1 Ultra) 6:50 Hash Tables 10:00 Hash Join 16:00 Cost of Hash Tables 20:00 Remapping Cost Hash Tables 22:30 Consistent hashing
Aggregate functions like Count, max, min, avg performance really depends on how did you tune your database for that kind of workload. Let us discuss this. 0:00 Intro 1:22 SELECT COUNT(*) 4:30 SELECT AVG(A) 5:15 SELECT MAX(A) 8:00 Best case scenario 11:30 Clustering 14:00 Clustering Sequential Writes 17:19 Clustering Random Writes 20:30 Summary
99% of phishing attacks can be avoided by looking at the URL. However this secuirty researcher proves that not enough. https://mrd0x.com/browser-in-the-browser-phishing-attack/
On March 8 2022 Spotify and Discord experienced an outage latest 2-3 hours. The reason was a configuration on the xDS formats on Google Traffic Director. Let us discuss how this change caused the outage and what Spotify did to mitigate that outage without relying on Google restoring the service back up. Resources Spotify outage https://engineering.atspotify.com/2022/03/incident-report-spotify-outage-on-march-8/ Google Cloud outage https://status.cloud.google.com/incidents/LuGcJVjNTeC5Sb9pSJ9o En...
The Russia-Ukraine Cyberwar has reached a peak this past week. In this video I explain the multiple ways a Denial of Service attacks can happen and how to protect against them Intro 0:00 What is DOS? 1:00 Long running requests 1:42 Crash backend processes 3:30 Exhaust Max connections 4:25 Large response (web traffic) 5:42 Lots of requests 8:27 Complex request (Regex bug) 9:57 Prevention 12:27
Fundamentals of Database Engineering udemy course (link redirects to udemy with coupon) https://database.husseinnasser.com Chrome, Edge and Firefox are approaching version 100. that version is 3 digit version where most websites only checked two digits. You can imagine what can go wrong. Lets discuss
On 2/22/2022 Slack experienced a 3 hours outage from 6AM to 9AM PST because of a configuration change. That change lead to increase load to their database infrastructure which causes queries to starve. Lets discuss https://status.slack.com/2022-02-22
It looks like there is demand for bringing QUIC and HTTP/3 to NodeJS, someone donated $1000 dollar to make it happen. However, what are the use cases for supporting HTTP/3 in Nodejs? I talk about whether HTTP/3 should come to NodeJS in this video. https://rysolv.com/issues/detail/863986ce-c8d5-466d-abf4-476d3177452d
Five major Canadian banks went offline for hours blocking access to online and mobile banking as well as e-transfers for customers. There are no reports of what might have caused the outage so In this video we explain what might have caused it. https://www.bleepingcomputer.com/news/security/canadas-major-banks-go-offline-in-mysterious-hours-long-outage/
NVMe changed the game of fast SSD storage. The spec is being extended to support networked storage, I have some doubts that would like to discuss in this video. Fundamentals of Database Engineering udemy course (link redirects to udemy with coupon) https://database.husseinnasser.com Introduction to NGINX (link redirects to udemy with coupon) https://nginx.husseinnasser.com Python on the Backend (link redirects to udemy with coupon) https://nginx.husseinnasser.com
I stumbled upon a research calculating how big of quantum computer required to break bitcoin public key encryption. It will take them 300 million quantum bits to find the corresponding private key given a public key. That wasn’t really the most instructive thing really from that research. The interesting thing is how bitcoin design carefully hides information about the original owner which makes breaking it really challenging. In this episode I discuss what does it take to break bitcoin encrypti...
NodeJS introduces importing network based modules in their latest release. Importing network based modules using `https:` and `http:` is supported under the `--experimental-network-imports` flag. This allows web browser-like imports to work in Node.js with a few differences due to application stability and security concerns that are different when running in a privileged environment instead of a browser sandbox. Import HTTPS https://github.com/nodejs/node/pull/36328/files...
I asked a question on my community post What port does your computer connect to when you visit google.com on your browser for the very first time? The answer really depends on the network configuration and that's what I discuss in this video. The answer could be HTTP port 80, HTTPS port 443, DNS port 53 or other answers that aren't even listed here including DNS over HTTPS and DNS over TLS. Lets discuss
In this episode of the backend engineering show I discuss the ramification of index page splits which results in fragmented index yielding slow query performance when using indexes. I go through what a page is, how a page is read and written in the database and finally discuss the current solutions to address this problem such as reindexing, fill factor and choosing a good index key type. Get my Fundamentals of Database Engineering Udemy course https://database.husseinnasser.com 0:00 Intro 1:50 ...
Multitenancy refers to placing two or more clients, customers or tenants so they share a single resource. The idea behind Multitenancy is to save on resources instead of giving each client its own resource (storage, app, memory, network etc..). You slice each part and give it to dedicated client. The number one rule is those tenants shouldn’t be aware of the existence of other tenants, they need to be completed isolated, no one tenant can read or influence the other’s tenant share. If this is co...
Scientists at the Physics and Engineering Department of the UK’s Lancaster University published a new paper describing ULTRARAM. A Low-Energy, High-Endurance, Compound-Semiconductor Memory on Silicon. I think this tech is a game changer but I still have my doubts. Let us discuss 0:00 Intro 0:30 RAM 4:00 SSD 11:00 UltraRAM 17:30 Doubts * RAM (Dynamic RAM) * Fast access with capacitors * random access * requires power to be refreshed * Flash NAND (SSD) * Pros fast random access (FTL) * Block stora...
enom my DNS registrar had an outage which took down my site husseinnasser.com lets discuss 0:00 Intro 5:00 How DNS Works 12:00 Outage report 16:00 Will I migrate my DNS? 21:40 Does decentralize mean anything anymore?
In this episode of the backend engineering show, I’ll discuss the low code movements and their pros and cons. 0:00 Intro 2:00 Evolution of Languages 8:40 Low Code Movement 10:00 Side Effect of Low Code 13:00 Leaky Abstractions Fundamentals of Database Engineering udemy course (link redirects to udemy with coupon) https://database.husseinnasser.com Introduction to NGINX (link redirects to udemy with coupon) https://nginx.husseinnasser.com Python on the Backend (link redirects to udemy with coupon...
These are some fundamental technologies that I want to explore in 2022. 0:00 The Way I learn 4:20 Database Engineering 7:00 Network Engineering 9:30 Hardware and Operating Systems 15:00 The problem with software engineering Collateral Knowledge Video https://www.youtube.com/watch?v=6YKbVpWmeLM&t=3s Become a Member on YouTube https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join 🔥 Members Only Content https://www.youtube.com/playlist?list=UUMO_ML5xP23TOWKUcc-oAE_Eg Fundamentals of Da...
Welcome to another dev tools video, in this video I use dev tools to break down how Tiktok website works to pull short-form content. We will use therock as a subject. It is an interesting episode, enjoy
In this episode of the backend engineering show, I explain the journey of an HTTP request that gets initiated from a click on a link. I discuss DNS, TCP, API Gateways, reverse proxies, load balancers, backend web servers, and much more. Become a Member on YouTube https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join 🔥 Members Only Content https://www.youtube.com/playlist?list=UUMO_ML5xP23TOWKUcc-oAE_Eg 🧑🏫 Courses I Teach https://husseinnasser.com/courses...
In this episode of the backend engineering show, I explain the journey of an HTTP request that gets initiated from a click on a link. I discuss DNS, TCP, API Gateways, reverse proxies, load balancers, backend web servers, and much more. Become a Member on YouTube https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join 🔥 Members Only Content https://www.youtube.com/playlist?list=UUMO_ML5xP23TOWKUcc-oAE_Eg 🧑🏫 Courses I Teach https://husseinnasser.com/courses...
Right after the latest patch log 4j 2.16, a new denial of service vulnerability surfaced on log4j resulting in a new 2.17 patch. Let us discuss. 0:00 log4dos 4:50 History of log4j fixes 15:20 All love to the open source maintainers Previous Backend Engineering show episode coverage of log4shell https://youtu.be/77XnEaWNups https://logging.apache.org/log4j/2.x/security.html# Become a Member on YouTube https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join 🔥 Members Only Content https://ww...
In this episode of the backend engineering show, we go through a deep dive to uncover the reason behind the outage on December 7th, 2021 Amazon outage. RCA https://aws.amazon.com/message/12721 All outage analysis videos https://www.youtube.com/watch?v=dhZ5--R42AM&list=PLQnljOFTspQXdkZLiYCCh_5RBP1-T-Rnx Get the Fundamentals of Database Engineering udemy course https://database.husseinnasser.com
