Preparation Guide For Your Next System Design Interview

Introduction

System design requires high-level thinking that is vastly different from working with components or low-level design.

System design interviews are geared towards evaluating how well you can design system architectures and make a set of components work together.

SaaS or other software needs to be pre-designed before the components are developed.

System Design works with not only the components but the interfaces, data, and modules that make the system function according to the requirements. Ideally, these interviews try to figure out how many technologies candidates are aware of while keeping in mind what their tradeoffs and substitutes are. 

What is the Purpose of System Design Interviews?

System design interviews are not focused on finding out if candidates are great with individual components, but rather, interviewers are more interested in how great a candidate performs when working on the system as a whole.

Software engineers will eventually need to sit for system design interviews in their career, even if not as a fresher, definitely when applying for higher positions. Thus, system design is a very important area to stress upon, and budding engineers must start preparing even before applying for software engineering roles.

However, if you have your interview in the next few weeks or days, then there are certain things you can do to perform better during the interview. 

To-do list: System Design Interview

You can also choose the best course for system design to prepare yourself for system design interviews. But, in order to fully impress your interviewer when designing a system, there are some things you need to keep in mind.

Defining requirements and specs effectively

The initial goals should be clear and the main functions that the service or application will have must be justified. For example, a social media application will have features such as hosting multiple users, uploading pictures, automating a news feed, and all the other necessary microservices.

Outline the high-level design before low-level designing

Candidates must first outline the design of the entire architecture before diving into individual components or details. This is necessary in order to avoid going too far in the wrong direction and confusing the right approaches in the process. This also saves time by ignoring the irrelevant specifics when there is not enough time.

Specify individual components alongside their interactions

This is the part where we can identify each component and what its role is in the system. Here, we must specify how the components interact with each other and what their tradeoffs are. We can also choose to discuss alternatives or substitutes that will result in better performance in different areas. Candidates must show a deeper understanding of the results of changes in each set of components as well, for example, discussing the data storage layouts or API of choice.

Declare the hardware specifications and prepare for deployment

This is the final step to acing the interview. Here, candidates must be careful when declaring the hardware that is required, for example, the number of machines that are required, the total RAM required, the CPU and processing power, bandwidth, and frequency of data.

Candidates may choose to talk about deployment approaches and the various options for deploying the project. Candidates are also expected to be able to answer how to scale the project or support more users parallelly. They can also choose to talk about the cost that will be incurred when running the machines or for the bandwidth. 

Common Interview Questions

System design best courses prepare candidates in designing the actual system or application but in order to face the interviewers from reputed companies, one must extensively practice the most common questions that are asked in system design interviews.

Here are some common questions that candidates are asked:

• Why use Django and not Flask?
• Did you employ a database? Which database did you use?
• How would you scale your past projects?
• What are some failures you have experienced in your projects?

Here are some services or applications candidates are asked to design:

• Social media or networking service
• URL shorteners
• Designing Uber
• Designing Twitter
• Video or audio streaming services like Netflix
• Consistent Hashing

Here is an example of what candidates are expected to build during system design interviews:

• Design a coffee shop management system in Flask.
• The system follows the SAAS approach and allows all the stores in the chain to log into the service.
• It has an API that inserts price, ingredients, shop ID, and stocks.
• The employees can check their timesheets and shifts through services such as Google calendar.
• The service has a hashing mechanism that allows unique identifiers assigned to employees, shops, and the menu.
• Use pytest for testing the units while Travis helps in building and testing every commit that is made to a GitHub repository.
• If tests are successful, then docker images are stacked in Dockerhub and deployed to Heroku.
• One can then use the ELK stack to monitor and log the performance.

Frequently Asked Questions

Key Takeaways

The best system design courses can definitely help get a better grip of designing full system infrastructures. System design online courses allow candidates to acquire an understanding of how high-level designing works.

However, in order to truly ace your system design interviews, practical experience is highly recommended alongside the actual deployment of projects. Candidates must go through the entire process of designing full architectures to truly analyze all their failures and successes.

This allows system designers to learn better methods of system planning and adopt more suitable approaches.