Database Replication - Sync vs Async | System Design Interview Prep
How do we scale Databases in Distributed System Design? What is Synchronous, Asynchronous and Semi-Synchronous Replication and how does it work?
Having multiple instances of databases is all cool - until you start thinking about consistency, latency, failover and the right balance amongst them. Its much more than copying data from one node to another - and that’s where interviewers really start to dig in.
In this latest video, I explain the challenges that reside with replicating databases and how to solve those challenges with different replication strategies like:
Synchronous Replication: When every write waits for all its clones
Asynchronous Replication: Speed at the cost of potential data "lag"
Semi‑Synchronous Replication: A middle ground for safety and performance
I’ve broken down each mode with real‑world examples and tradeoffs along with some code examples so that you can try all of it yourself.
▬▬▬▬▬▬ TIMESTAMPS ▬▬▬▬▬▬
00:00 Intro
01:02 Why Scaling Databases is Hard
02:38 Primary - Secondary Architecture
04:36 Asynchronous Replication
06:00 Synchronous Replication
07:57 Semi - Synchronous Replication
09:50 Demo & Code Examples
13:47 Summary
▬▬▬▬▬▬ OTHER VIDEOS ▬▬▬▬▬▬
System Design Playlist: • System Design Interview Prep For Beginners...
Microservices: • What are Microservices? Microservices vs M...
Load Balancers: • Load Balancers & Its Algorithms - System D...
Horizontal & Vertical Scaling: • Scalability in System Design - Horizontal ...
SQL vs NoSQL: • The Only NoSQL Video You'll Ever Need - S...
HTTP Rest APIs: • What are HTTP REST APIs? | GET, POST, PUT,...
▬▬▬▬▬▬ CODE EXAMPLES & DOCUMENTATION ▬▬▬▬▬▬
Code Examples: https://github.com/monisyousuf/youtub...
▬▬▬▬▬▬ SOCIALS ▬▬▬▬▬▬
Instagram: / monis.yousuf
LinkedIn: / monis-yousuf
Youtube: @MonisYousuf
My Website: https://monisyousuf.com
▬▬▬▬▬▬
This video is a part of the complete System Design Interview Series aimed at cracking FAANG/MAANG/Product Based Company interviews. The series explains foundational concepts like Load Balancing, Microservices, Horizontal and Vertical Scaling, Database Replication, Data Partitioning, Sharding, Consistent Hashing, CAP Theorem, Consistency and Caching. You can see the full course here: • System Design Interview Prep For Beginners...
On this page of the site you can watch the video online Database Replication - Sync vs Async | System Design Interview Prep with a duration of hours minute second in good quality, which was uploaded by the user Monis Yousuf 14 July 2025, share the link with friends and acquaintances, this video has already been watched 2,746 times on youtube and it was liked by 138 viewers. Enjoy your viewing!
