The 9th Nine
Welcome to The 9th Nine.
If you’re reading this, you probably care about more than just “getting it to work.” You care about what happens after it works. When the traffic spikes. When the database locks up. When the third-party API goes silent.
I’m Walid Chebbi, a senior backend engineer. I built this place to document the realities of building distributed systems.
What to expect
This isn’t a tutorial site for beginners. There are plenty of those (and they’re great). This is a place for mid-to-senior engineers to discuss:
- Systems Thinking: How individual components interact to create complex behaviors (and failures).
- Trade-offs: Every architectural decision is a compromise. We’ll explore the costs of the choices we make.
- Production Realities: The difference between theory and the messy reality of deployed software.
Why “The 9th Nine”?
High availability is often measured in “nines.” Five nines (99.999%) is the gold standard for many systems—about 5 minutes of downtime per year.
The “9th nine” is an asymptotic goal. It’s the pursuit of perfection that we know we can never fully reach, but the pursuit itself makes our systems stronger, more resilient, and more honest.
Let’s build something checking.