My Personal Background In System Design
In April 2008, I joined an internal team at Microsoft working on a large-scale project building a distributed storage solution.
Amazon had launched their Simple Storage Service in 2006, and Google launched their PaaS solution Google App Engine the same month I joined the team, so we were in the early land grab of cloud computing. Less than two years later, that project was launched to the world as a new product category: Microsoft Azure.
When I joined the Azure team, I came from working on Exchange. I understood server storage and client management, but not at this scale, and certainly not distributed across the world. It required a lot of learning on the job.
Today, the lessons myself and other cloud engineers learned in those early days are codified into the System Design discipline. Now for many companies, the System Design Interview is instrumental in the developer interview process which means it is vital for landing a job and setting your career on a good trajectory.
Note: at Educative we recently published our most comprehensive System Design resource yet: Grokking Modern System Design for Software Engineers & Managers. This course covers 13 of the most common system design interview questions and teaches you how to solve them through a modular building blocks approach. Its a great resource for any engineer hoping to level up their career.
How To Solve Problems On Leetcode
There are several tips for the most optimal problem solving on Leetcode:
- Avoid using IDEs or any code editors, and solve the problem right in the web editor on the Leetcode page, or on a whiteboard. In the real interview, you won’t get to write your code in the real IDE as well, so it is better to get used to that.
- Don’t rush to read the solution too fast â give yourself some time to think about the problem yourself. After all, you are not only learning how the problems are solved, but also training your brain to come up with the solutions. If you are stuck on a problem, it is okay to spend several hours or even days to think about it before giving up.
- After you solved the problem, be sure to check its official solution and several top solutions from the discussion page. This way you may learn about some better ways to solve the problem. Also, check some solutions in your programming language to see what you may learn from the code.
- Be sure to write good code in your solution. Generally, during the interviews, you are expected to write clean, well-styled code, like something that you may write at work.
Key Features / Requirements
- The user can register and delete an account, and recover its password.
- The user can post within seconds, and it may contain text, images or videos.
- The user should be able to see timelines, including a user timeline which shows his/her own posts, home timeline which includes posts from those he/she follows and search timelines via keywords.
- The user should receive notifications through email or mobile app of new posts from those they follow.
- Users posts should be available to all the followers within seconds.
- The user can follow another user
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What Is A Systems Design Interview
Systems design interviews is an important part of tech interviews at FAANG and tier-1 tech companies. In these interviews, companies evaluate your ability to create scalable systems with low latency, capable of reaching millions of users.
These interviews typically consist of many open-ended interview questions, where you essentially have to discuss the technicalities behind complex, scalable systems. Knowing and applying concepts related to relational databases, sharding techniques, and network protocols is also crucial to ace this round.
What Are System Design Interviews
System design interviews typically test the knowledge and design skills of professionals seeking an upper-level position in a technological field. In system design interviews, applicants answer broad questions by developing a prototype system using key components to outline a model before explaining their approach. Interviewers may also ask job candidates questions to determine their technical knowledge and experience. They are commonly used for roles like development manager, system engineer or technical program manager.
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How To Nail Your Next Tech Interview
Google is one of the most valuable companies in the world and offers a broad spectrum of consumer- and business-centric services. Its phenomenal culture makes it one of the best companies to work for software engineers and developers. As part of its technical interview process, Google conducts a systems design round to evaluate the engineering design skills of applicants. This round mostly happens during the on-site interview, along with the coding and behavioral rounds.
To ace Googleâs system design interview requires a good understanding of design fundamentals and the ability to build and work with scalable systems.
This article focuses on acquainting you with and what sort of systems design interview questions to expect.
Hereâs what we will cover in this article:
- What is a system design interview?
- Google system design interview process
- Google system design interview questions
- Tips to prepare for and crack system design interview
Interview Questions For System Designers
The Indeed Editorial Team comprises a diverse and talented team of writers, researchers and subject matter experts equipped with Indeed’s data and insights to deliver useful tips to help guide your career journey.
An interview for a system designer position is an opportunity to discuss your experience and abilities and to showcase your skills at creating complex systems. You can prepare for your job interview by studying basic design principles and preparing answers to possible questions about them. In this article, we review common questions and answers for a system design interview to help you prepare.
Related: Top 6 Common Interview Questions and Answers
Jenn, an Indeed Career Coach, breaks down the intentions behind employer’s questions and shares strategies for crafting strong responses.
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Design A Social Media App
One of the most common system design interview questions, design a social media app requires candidates to tackle an incredibly complex taskbuilding a large, intricate system in 60 minutes or less. For this example, well assume the interviewer asked us to design Twitter.
Ask clarifying questions
- Is the interviewer looking for a design of the core features, or a high-level overview of the whole service?
- What are the constraints of the system?
- What are your assumptions?
- Back-of-the-envelope calculations: average KBs per tweet, size of new tweet content per month, read requests and tweets per second, etc.
- High-level components: write, read, and search APIs types of databases SQL vs NoSQL etc
Drill down on your design
- Potential bottlenecks: adding a load balancer with multiple web servers, scalability issues, fanout service slowing down tweets and @replies, etc.
- Components that you could dive into: how a user views the home timeline or posts a tweet, the intricacies of the database design, etc.
Bring it all together
- Consider: does the final design address the bottlenecks youve identified? Does it meet the goals you discussed at the beginning of the interview? Do you have any questions for the interviewer?
For a full answer to this question, take a look at the video guide below from Success In Tech or this text guide from donnemartin on GitHub.
Grokking Leetcode: A Smarter Way To Prepare For Coding Interviews
To LeetCode or not to LeetCode? What if you dont want to practice 100s of coding questions before your next coding interview?
There is a part of me that dislikes coding interviews, primarily because it requires me to spend a lot of time preparing for coding questions. Moreover, during an interview, I have to present a reasonable
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What Is Required To Design A Garbage Collection System
Garbage collection ensures a Java system is running appropriately and frees a programmer from having to do it manually. Hiring managers look to see if you know how to truly design the ins and outs of various systems. A GC makes systems memory efficient.
Example:”One of my recent clients needed a way to have more memory, but there was an issue with always having to go in and deal with memory deallocation. The nature behind garbage collection is to make a system appear as if it has a seemingly endless amount of memory. What is really happening is that the system is re-purposing the memory. When a system is running slowly, a garbage collector goes in and collects what is no longer being used. I set up their system so that if an object is referenced or recursive in nature, it remains. Next, it goes through methodically and marks whatever has not been referenced and sweeps only that. Using the mark and sweep method with the void command helps to repurpose and open up memory no longer being used. With this in place, my client had a faster system with less maintenance required.”
Cracking System Design Interviews
Software Development Engineer III at Amazon | Amazon Bar Raiser | ex-Yahoo
Today we hosted a Clubhouse room on the topic of “Cracking the System Design Interviews”. System design is one of the critical areas that most of the major tech companies like to probe the candidates, there is usually at least one System design interview round starting from mid-level engineering interviews, there may be more depending on the seniority of the role. System design interviews require upfront preparation and deep knowledge into core distributed system concepts, along with problem solving skills, ability to trade-off between multiple possible approaches and articulate the reasoning behind choosing one approach over the other. The system architecture powering the tech companies like Netflix, Instagram, Twitter was not built in a day, it took months. Then how do we tackle questions like “Design a photo-sharing service like Instagram” or “Design social-networking service like Twitter” during an interview in 20-30 minutes?
The Clubhouse room witnessed a few really interesting questions that triggered pretty insightful conversations. Thanks to our panelists Swetha Konnireddy, Vivek Kirubanandan, Bharath Reddy Janumpally, Sharath Honnaiah, Gaurav Savla for joining today’s discussion and sharing their valuable inputs.
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How Do You Prepare For A System Design Interview
Unlike a coding interview question, System Design Interviews are free-form discussions, and theres no right or wrong answer. Instead, the interviewer is trying to evaluate the candidates ability to hold a conversation about the different aspects of the system and assess the solution based on the requirements that might evolve during the conversation.
The best way to think about the conversation is to imagine that you and a colleague are asked to design a large-scale system, and you are hashing out the details on the whiteboard. You are understanding the requirements, scope, and constraints before proposing a solution.
So how do you design a system in an interview if you have never built one in real life? To crack your system design interview, youll need to prepare in three areas:
Each of these dimensions flows into the next.
If you dont know the fundamentals, you wont be prepared to architect a service if you dont know how to put those systems together, you wont be able to design a specific solution once youve designed large-scale systems, you can take lessons learned and integrate them into your base knowledge.
Lets look at each of these dimensions in order.
What I Learned Through Hundreds Of System Design Interviews
The experience of working on web-scale systems at Facebook and Microsoft taught me two key skills to approaching the System Design Interview:
Heres the counterintuitive part: in the System Design Interview, companies are not actually trying to test your experience with System Design.
Successful candidates rarely have much experience working on large-scale systems, and interviewers know this. Again, this is a discipline that has only been around for about fifteen years, and like everything else in software engineering, it is evolving rapidly.
The key is to prepare for the SDI with the intent to apply that knowledge.
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Can You Name Some Metrics For Measuring System Performance
Interviewers may ask you this question to find out if you understand the different ways to measure system performance and the importance of these monitoring techniques. When you answer, explain how these metrics help ensure a fast and efficient system.
Example:”The three most common metrics used to measure a system’s performance are availability, latency and throughput. These metrics help system designers measure the speed of a user’s experience while interacting with a system. Availability shows us how often a system responds to a user in a ratio of Uptime vs. Downtime. Latency refers to the speed at which a message is delivered in milliseconds. Finally, throughput measures the amount of data that successfully travels through a system to a user in a specified time period. Throughput is typically calculated in bits per second.”
Topics To Prepare For Systems Design Interview
The systems design interview rounds aim at testing how you break down a large problem and tackle different parts of it. So while your tech skills are important, your critical thinking is also at display during these rounds. Narrowing down the topics to prepare for such an interview is not easy.
However, based on our experience of training over 9,000 software engineers, the following are some of the key broad categories that you should consider while preparing for a systems design interview:
- Basics of systems design
- Measuring the performance of scalable systems
- MapReduce and distributed file systems
- Systems design case studies
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How To Prepare For System Design Interviews
As you can see from the complex questions above, there is a lot of ground to cover when it comes to system design interview preparation. So its best to take a systematic approach to make the most of your practice time, and we recommend the three steps below.
For extra tips and resources, take a look at our system design interview prep guide and our list of 19 system design interview tips from ex-interviewers.
Use The Star Response Technique
Formatting your responses using the STAR interview response technique is a strategy to help you craft answers that illustrate your knowledge and qualifications through specific experiences. STAR is an acronym for Situation, Task, Action and Result. Using the STAR method, discuss an applicable situation, identify the task you needed to complete, outline the actions you took and reveal the results of your efforts to demonstrate your skills to the interviewer.
The Architecture Of Large
You would have to learn about topics like:
Processing happens at various levels in a distributed system. Some processes are on the client, some on the server, and others on another server – all within one application. These processing layers are called tiers, and understanding how those tiers interact with each other and the specific processes they are responsible for is part of system design for the web.
HTTP and REST
HTTP is the sole API on which the entire Internet runs it is the system through which we send every email, stream every Netflix movie, and browse every Amazon listing. REST is a set of design principles to directly interact with the API that is HTTP, allowing efficient, scalable systems with components isolated from each others assumptions. Using these principles and open API makes it easier for others to build on your work or extend your capabilities with extensions to their own apps and services.
DNS and Load Balancing
If you have 99 simultaneous users, load-balancing through DNS routing can ensure that servers A, B, and C each handle 33 clients, rather than server A being overloaded with 99 and servers B and C sitting idle. Routing client requests to the right server, the right tier where processing happens, helps ensure system stability. You need to know how to do this.
What Is A System Design Interview
A system design interview is conducted to allow candidateslike programmers, designers, developers and software engineerssufficient opportunity to prove expertise in the field through the tangible application of knowledge to solve a real problem that a company might be facing.
The system design interview is typically conducted later in the interview process. It is a trial intended to see how well you work on a team and your approach to problem solving using open-ended questions to arrive at the best possible solutions. A system design interview analyzes your process in solving problems and creating designing systems to help clients. It is an opportunity for you to show the hiring manager and potential team that you are a valuable asset and display your skills and expertise in a concrete way.
System Design Interview Questions And Answers
System design questions are typically ambiguous to allow you the opportunity to demonstrate your qualifications. You can ask questions before you respond to help you narrow the scope, give you direction and clarify any expectations.
Here are six common questions you may be asked during your system design interview:
How Would You Design A Tinyurl System
A hiring manager might ask this to allow you the opportunity to show your solid foundation in design with a detailed explanation and a specific example. Prove your understanding that a TinyURL is an URL service that creates a shorter, unique URL after users enter a long URL. Consider focusing on other basics not listed in the example response like how you create a unique ID for each URL, how you handle redirects and how you delete expired URLs.
Example:”When I was working for a public instant messaging site, I created a simple system where every message was limited to 140 characters. It also necessitated shortened URLs of about 30 characters. This TinyURL system is also useful when entering hyperlinks in emails or on a smartphone, where there is room for error.
TinyURL is also a perfect example of the hashtag table. This data structure associates keys with values and is a simple connections code. By using this basic 16-bit hash table, I was able to optimise usability and meet the needs of the system.”
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