All About System Design

System design is the foundation of creating scalable, reliable, and maintainable software. It involves defining how different components within the system will interact with each other, how data will flow from start to end, and how the system can adapt to changing demands. In this article, we will discuss all the basics of system design and how we can approach design problems.

What is system design?

System design is all about the architecture of software. It involves laying down the blueprint of how software systems will work. We list the components, design how they will interact with each other, how the data will flow into various components, and how it will meet the scalability requirements. We may need to plan for designing a system that can scale to millions of users or ensure that the system has high availability with strict uptime.

System design is not limited to choosing which tools or technologies we will use; it is also about understanding the problem we aim to solve, who will use the system, and the limitations under which the system must operate.

Why do we need system design?

In today's world, several applications, such as social media platforms, e-commerce stores, gaming platforms, and food delivery apps, handle a huge amount of load and provide real-time interactions with consistently high availability. Without careful design, these systems may fail as the load increases, leading to frustrated users and financial losses. A well-designed system ensures:

• Scalability: The system can scale as the user base and data increase.
• Reliability: The system minimizes downtime and ensures smooth operations.
• Efficient: The system runs efficiently without requiring high-end hardware for good performance.
• Maintainable: It is easy to update, modify, or extend the system as needed.

Building Blocks of System Design

Every system is made up of several important components. Let's take a look.

Clients

A client is the system's entry point. Clients are end users, either humans or machines, like web browsers, mobile apps, or IoT devices. They interact with the system by sending requests and expecting responses.

When designing for clients, we address latency, network challenges, and user experience.

Servers

A server handles client requests, processes data, performs calculations, and sends results back. Servers can be:

• Application Servers: Contain business logic.
• Web Servers: Serve static content like HTML or images.
• Database Servers: Store and query data.

We must decide between monolithic and microservices architectures, each with benefits and trade-offs.

Databases

A database server stores and manages user data. It can save, retrieve, and process data. Common types include:

• Relational Databases (SQL): For structured data with consistency needs.
• Non-Relational Databases (NoSQL): For unstructured data, offering scalability.

Networking

Networking connects system components, enabling seamless communication between clients, servers, and databases. Key elements include:

• Protocols: HTTP/HTTPS or TCP/IP.
• Load Balancers: Distribute traffic to prevent bottlenecks.
• Content Delivery Networks (CDNs): Cache and deliver static content close to clients.

Think like a system designer

System designers must view design problems as a whole. Instead of rushing to solutions, it is essential to break down problems into smaller parts and focus on their interactions.

For example, when designing a food delivery app, a system designer should consider:

1. How to handle thousands of user orders?
2. How to ensure users see real-time delivery partner locations?
3. How to manage demand surges without affecting performance?

A system designer's role is to balance the system's capabilities with limitations like cost, technology constraints, and user expectations.

How to approach a system design problem?

System design problems should be approached step by step for better results. Designing systems is an iterative process, and systems evolve as requirements change or new ones arise. For initial designs, we can follow these steps:

1. Understand the requirements: Clearly define what the system should do. Does it need low latency, high throughput, or consistent data?
2. Identify core components: Break down the system into smaller building blocks like clients, servers, databases, and network components.
3. Design for scalability and reliability: Plan for techniques like load balancing, caching, and database sharding to handle growth and prevent failures. These can be implemented later as the system grows.
4. Consider trade-offs: Identify acceptable compromises based on the system's priorities.
5. Iterate and improve: Share your design with peers and gather feedback. Refine it to ensure all requirements are met.

That's the introduction to system design. In upcoming chapters, we will dive deeper into each individual component.