"Databases do not scale easily - know your limits Anon"
- Arpit
We all build horizontally scalable systems, but scaling is not as simple as saying "just add more machines" or "I will configure an autoscaling group". The challenge comes when we design systems that continue to behave predictably as traffic and load increase.
Here are some common things you will run into and the pointers that will help you when you are building systems that scale horizontally:
1. Cache everything that can tolerate stale reads
2. Handle noisy neighbors with CPU/memory limits
3. Keep services stateless - scaling becomes easy
4. Databases do not scale easily - know your limits
5. Know your data access patterns before partitioning
6. Queue asynchronous work to absorb traffic spikes
7. Design for failure - retries, timeouts, fallbacks
8. Eliminate single points of failure
9. Make operations idempotent - handle retries safely
10. Understand consistency tradeoffs early
11. Invest in observability - metrics, logs, and tracing
12. Avoid distributed transactions where possible
13. Rate limit critical services and APIs
14. Scale reads and writes differently
15. Capacity planning still matters despite autoscaling
By no means is this exhaustive, but these are some of the most common considerations that tend to surface as systems grow.
Hope this helps.