# Q4 - Scalability and Load Balancing

## 1. Architecture Overview

The application is deployed behind a Load Balancer that distributes incoming traffic across multiple application containers.

Components:

- Users
- Load Balancer
- Container Cluster
- Ghaymah Block Storage
- Database

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## 2. Required Number of Containers

Application Load = 15,000 requests/second

One Container Capacity = 500 requests/second

Required Containers:

15000 / 500 = 30 Containers

Safety Margin (30%):

30 × 1.30 = 39 Containers

Final Answer:

**39 Containers**

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## 3. Cold Start Strategy

To reduce cold start latency:

- Keep a small number of warm containers running.
- Enable Auto Scaling based on CPU and request rate.
- Perform health checks before routing traffic.
- Register new containers with the Load Balancer only after becoming healthy.
- Use lightweight container images for faster startup.

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## 4. Ghaymah Block Storage

Block Storage is used for stateful workloads such as databases.

Benefits:

- Data persists even if containers restart.
- Supports high availability.
- Can be attached to replacement containers.
- Suitable for MySQL, PostgreSQL, MongoDB and other databases.