# 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**

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## 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.

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## 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.