Google System Design Interview Questions

Mehdi K. - "It would be good to talk about the impacts on costs as well"See full answer

V V. - "Simple file system ( Hash Map , LSM trees), and consistent hashing. I failed to discuss about conflicts ( Versioning)"See full answer

Qusai B. - "Assumption: I’m estimating the minimum number of trains required to fulfil maximum demand I’m including all trains that’s serving NYC Formula: Before I state my formula, I would like to mention a few things I will be calculating the number of trains required to fulfill all demand at the peak time during a workday. I assume peak time lasts for 2 hours I’m assuming that a train takes 2 hours to complete one roundtrip on its route, which means any given train can service rider"See full answer

P K. - "Note: Modifying the question to reflect the storage cost as well. Question: Estimate the cost of storing google photos on the photos app? Clarifying questions: Google photos - an app that syncs automatically to your camera app and uploads photos to Google cloud and reduces the need to store it on your device Cost of 1GB storage $0.002 Time storage cost per year Equation: Cost of storage per year = average cost of storing photos per day x 30 days x 12 months The ave"See full answer

James H. - "I broke the vehicles down by regions in the world. Designed a wireless api interface to sync with a database backend that linked to google maps through another service and api."See full answer

Bini T. - "I understand this is more focused on ML. However, I have a system question. If users allow us to access their location, or they send location via text box, could we use CDNs for the search without hitting our database? We only query the database when we have zero information on location. Other questions: does embedding always guarantee information on location? Do we discharge the user images after we return a prediction? I heard the feedback that we should keep it for future learning. What would"See full answer

Ven E. - "I saw this question in one of my interviews."See full answer

Gk K. - " can we use blomfilters to check existing usernames? and if both are creating at a time, like both are choosing some abcd , here system checks whether user with that name exists or not. so while checking , it will add an entry on redis (example) with this name as key and obtain lock using some distributed lock. , it will lock on that name. (like seat booking in bookmyshow) with some TTL value. so this check will happen once user enters his interest username and also while submit .. 2 times che"See full answer

Claudia S. - "What is a "cache controller"? With no more details it's difficult to tell what this question is about."See full answer

Sourabh G. - "Functional Requirement Monitor health, metrics Alert in case of failure/anomaly Visualize the live health Analyse machines on periodic basis Non Functional Should not exert load on machines low latency Highly scalable Logs/Metrics Gathering push - machine gather and send to system and low priority background thread along with batching pull - heart beat check (for offline machines) Processing Real time streaming using Kafka/kinesis + Flink TimeSeries database for stor"See full answer

Akshai V. - "Google Assistant is the Voice AI which converts Natural Language to Queries/Instruction , processes it and get the results and again converts it back to Meaningful Results to the User Currently Google Assistant is Integrated in Multiple End Points. Phone Google Home Chrome Cast Google Chrome Books Some of the Use Cases Google Assistant is used is Making Phone Calls/Texting Asking General Queries/Searching for Information Integration with Devices and Turning them O"See full answer

Kavya C. - "MTBF is Mean time between failures. This is measured to figure out how reliable a system is by what is the gap between 2 failures. (Total time elapsed- Down time)/No of failures"See full answer

Anonymous Hyena - "A load balancer accepts requests from clients (e.g. web browsers on the Internet) and backend services (e.g. a web server). Load balancers are useful for replicating backend services onto multiple machines to meet increased demand. The design of a load balancer should address the following questions: What protocols should be supported? IP allows computers to communicate using packets, similarly to how people send letters. IP packets are addressed using an IP address and port number. "See full answer

shg - "(This was not search autocomplete based on prefix matching question.) First of all, please note :- The interviewer is not expecting you to get to the right answer in just 1 hr. These systems have been designed over months and improved over years and its impractical for anyone to expect you to get to the right answer in 1 hr. (There is no one single right answer). At the end, the interviewer (director level person) told me the same. What they are looking for is your thought process, getting from"See full answer

Vidur K. - "Clarifying Questions First, let me try to clarify what kind of self-driving car are we talking about here. Let' say, we have the following top-level assumptions: Fully autonomous Family Sedan Car US Market This technology is only available with Google In a real face-to-face interview would pause to ask the interviewer to correct assumptions or ask for other features. Consumer Family - uses the autonomous ability of the car to spend time with kids while dropping them off to"See full answer

Xash C. - "This one is a great example of Build, Borrow, or Buy strategy framework (http://www.build-borrow-buy.com/build-borrow-or-buy-in-practice/) - explore and evaluate three different approaches: organic growth and building a product from scratch (e.g. Amazon building its own Amazon Restaurants service), partnering with an existing provider (e.g. enterprise-level partnership with Instacart or Lyft), or acquisition growth (e.g. Uber acquiring Postmates). Evaluate which approach makes sense for the com"See full answer