Complete Q4: Scalability

q4-scalability/calculations.md

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+# Scalability and Load Balancing
+
+## 1. Required Number of Containers
+
+### Given
+
+- Incoming traffic = **15,000 requests/second**
+- One container can handle = **500 requests/second**
+- Safety margin = **30%**
+
+### Calculation
+
+Required containers without margin:
+
+15000 ÷ 500 = **30 containers**
+
+Adding a 30% safety margin:
+
+30 × 1.30 = **39 containers**
+
+Rounded up:
+
+**40 containers**
+
+---
+
+## 2. Cold Start Strategy
+
+To reduce startup delays during traffic spikes, the following strategy is recommended:
+
+- Keep at least 2 containers always running.
+- Enable Horizontal Pod Autoscaler (HPA).
+- Cache container images on cluster nodes.
+- Use lightweight Docker images.
+- Configure Readiness Probes before sending traffic to new containers.
+- Scale gradually to avoid resource spikes.
+
+---
+
+## 3. Using Ghaymah Block Storage
+
+Ghaymah Block Storage should be used for stateful workloads that require persistent storage.
+
+Examples include:
+
+- PostgreSQL
+- MySQL
+- MongoDB
+
+Benefits:
+
+- Data persists even if a container restarts.
+- High reliability.
+- Easy storage expansion.
+- Suitable for production databases.