Design An Efficient Parking Lot System - System Design

System requirements

Functional:

Build two level parking lot's
first floor - 100 cars
second floor - 150 cars
entry/exit point in ground floor
entry/exit point from second floor
short term parking
long term parking
payment - credit card only

Non-Functional:

ACID compliance
availability & eventual consistency

Capacity estimation

Throughput
1200 cars/day
1200/24 = 50 cars/hour
1 car/minute (payment transaction)
Memory
10MB/day
5 years = 1 PTB

API design

Get

vehicle make
vehicle model
vehicle type
car plate number
location state
location city
location zipcode
parking spot
date
time
short term/long term parking
parking ticket

Return

vehicle make
vehicle model
vehicle type
vehicle plate number
location state
location city
location zipcode
parking spot
date
time
parking ticket
short term/long term parking
payment confirmation yes/no

Database design

SQL database schema
vehicle make
vehicle model
vehicle type
vehicle plate number
location state
location city
location zipcode
parking spot
date
time
parking ticket
short term/long term parking
payment confirmation yes/no

High-level design

Database - SQL
payment involved hence meet the ACID compliance
Loadbalancer
Nginx to distribute the traffic across multiple servers
cache
redis to store all the vehicle make and model information to determine if they fit into the parking lot or not
Payments
use the third party provider - ayden for processing the transactions

Request flows

Explain how the request flows from end to end in your high level design. Also you could draw a sequence diagram using the diagramming tool to enhance your explanation...

Detailed component design

SQL
given the traffic and through along with the payment information SQL will meet the requirements
Redis
out of the box redis which can be added to the DB can hold data that will meet the requirements

Trade offs/Tech choices

Failure scenarios/bottlenecks

Try to discuss as many failure scenarios/bottlenecks as possible.

Future improvements

What are some future improvements you would make? How would you mitigate the failure scenario(s) you described above?