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q4-scalability/calculations.md

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+# Scalability Calculations
+
+## Requirement
+
+Design an architecture capable of handling **15,000 requests per second**.
+
+---
+
+## Container Capacity
+
+Each container can handle:
+
+- **500 requests/second**
+
+---
+
+## Required Containers
+
+Without safety margin:
+
+15000 / 500 = 30 containers
+
+---
+
+## Safety Margin
+
+A 30% safety margin is required.
+
+30 × 1.3 = 39 containers
+
+---
+
+## Final Result
+
+**39 containers** are required to safely handle the expected traffic.
+
+---
+
+# Cold Start Strategy
+
+To reduce startup latency for new containers:
+
+- Keep 2–3 warm containers ready.
+- Use lightweight Docker images.
+- Configure health checks before routing traffic.
+- Trigger auto-scaling at 70% CPU or 80% memory utilization.
+
+---
+
+# Using Ghaymah Block Storage
+
+Ghaymah Block Storage is used for stateful workloads where data must persist even if containers are recreated.
+
+Typical use cases include:
+
+- PostgreSQL
+- MySQL
+- MongoDB
+- Application uploads
+- Persistent logs
+- Backup storage
+
+Application containers remain stateless, while persistent data is stored on Block Storage.