10 Must Know System Design Concepts for Interviews

Competing in the cutthroat battlefield of technical interviews, an aspiring software engineer needs to master system design concepts. Be it a tech giant or a promising start-up one is dreaming about joining, showing a profound knowledge of the following principles may make one stand out.

Here are 10 system design concepts one needs to know to nail the next interview:

1. Scalability:
   Scalability implies a system’s ability to handle a growing amount of workload or increasing user bases without compromising performance. Designing systems that can expand with demand requires an understanding of horizontal or vertical scaling, sharding, and load balancing techniques.
   
2. Availability:
   Availability is a metric that refers to a system’s response to user requests. High availability entails preparing systems with redundancy, fault tolerance, backup, and recovery mechanisms in the event of disaster or other remedial measures to prevent downtime and ensure interrupted service.
   
3. Reliability:
   Reliability is the core principle of system design ensures the system operates as expected in different conditions and failure scenarios. Fault tolerance, error handling, and graceful degradation techniques are utilized to develop reliable systems upon which users can depend.
   
4. Data Modeling:
   Data modeling is highly vital in database design in ensuring that databases scale and work effectively. Given an understanding of the kinds of databases and database best practices such as normalization, denormalization, and indexing, engineers can determine the best approach to data storage for their applications.
   
5. Design Patterns:
   Design patterns are a set of predefined practices for designing software with architectures. They include architectural patterns like MVC, MVVM, Microservices, behavioral, and creational patterns that make systems flexible and maintainable.
   
6. Security:
   Security is a key factor in system design, as without it, the systems we design will not be safe. Authentication, authorization, encryption, and the principle of the least privilege are common words and concepts for engineers working with building secure systems that can withstand cyber threats.
   
7. Real-world Experience:
   Gaining real-world experience through projects, internships, or open-source contributions is critical to improving one’s system design skills. Practical exposure enables you to apply theoretical concepts in practice settings and obtain insights and lessons that no book can teach you.
   
8. Load Balancing:
   Load balancing is an essential dimension of designing high-performance and scalable systems, more so in distributed architectures. It refers to the process of spreading incoming network traffic across multiple servers or resources to optimize resource utilization and prevent the overloading of any one component. They play the role of intermediaries between the clients and the servers, smartly routing requests based on the health status of the server, its response time, and load at any given moment.
   
   There are several load balancing algorithms that are commonly used:
   Round Robin: Requests are cycled across servers, irrespective of their current load and capacity.
   Least Connection: It ensures equitable distribution of the load. It means the request is sent to a server with the least number of active connections. This approach is used to distribute the load more evenly.
   IP Hash: The server that receives a request, based on the client’s IP address, will receive all subsequent requests from this client.
   Weighted Round Robin: Different weights are assigned to the servers depending on their capacity or performance. Hence, servers with high weights get more traffic.
   
9. Performance Optimization:
   Performance optimization refers to the process of speeding up performance and expression occurrences or the performance of a computer in general. Sequentially, it is about orienting the unit or pieces of equipment to render efficient or optimal performance.
   
   The following are some common examples of performance optimization:
   
   Code Optimization:
   Identifying and optimizing inefficient algorithms and data structures or code paths to reduce execution time and resource usage. This is done to maximize the performance of CPUs, memory, network, storage, and other resources.
   Database Optimization: Tuning a database query, indexing frequent queries, or optimizing the way data is stored in the database is an option. The query should be made as quickly as possible, and the database as a whole should be logically stored.
   Caching: As a resource locality enhancing solution, frequently accessed data/items or results of the most costly computations are kept in cache memory so they may be accessed swiftly rather than computed/queried again.
   Concurrency and Parallelism: Using multi threaded processes, asynchronous processing, parallel computing techniques, and so on to minimally use CPU resources and maximize system resources.
   Content Delivery Networks (CDNs): Distributing static content among geographically different servers. It helps avoid latency and saves bandwidth, particularly if the application has a global audience.
   
10. Caching Strategies:
    Caching is the primary technique for speeding up web application performance and scalability. The idea is to store frequently used data or computations in temporary storage, so-called a cache. Caches can be applied at different levels of the application stack, from the client-side to the server-side and database.
    
    Common caching strategies are:
    
    Client-Side Caching: The browser caches such static assets as js files, stylesheets, and images to avoid redownloading these files for subsequent visits, which reduces page load time.
    Server-Side Caching: Application servers cache dynamic content and database query results to avoid processing time and database load when repetitively receiving identical requests. This is typically accomplished on the server side through methods like in-memory caching utilizing tools such as Redis or Memcached.
    Content Delivery Network (CDN) Caching: CDNs cache static content at edge locations placed worldwide. This makes it easier to serve content to users by doing so from the closest possible CDN server to them rather than waiting for it to transfer from the origin server, having it delivered even more quickly.
    Database Caching: Database query results or popular database-stored data can be kept in the memory. Thus, there is no need to execute complex queries whenever the same query is made.
    Full-Page Caching: Web pages or portions of them can be cached to provide pre-rendered content to users and hold down server load or loading times, particularly for content or dynamic websites.
    

Conclusion
Now that you are aware of these 10 fundamental system design principles, you’re ready to confidently and competently face any technical interview, no matter how difficult it might be. Finally, remember that you should not just memorize these ideas, but also practice using them in various real-life situations—because practice is an essential part of becoming a skilled system designer. Good luck with your interview preparation!