System Design Quiz

Question 1

The CAP theorem states that a distributed system can guarantee at most two of…

Accepted Answer

Consistency, Availability, Partition tolerance

Answer

Consistency, Availability, Performance

Answer

Caching, Availability, Persistence

Answer

Concurrency, Atomicity, Partitioning

Question 2

What is horizontal scaling?

Accepted Answer

Adding more machines to distribute load

Answer

Adding more CPU/RAM to a single machine

Answer

Compressing data

Answer

Caching responses

Question 3

A load balancer’s primary job is to…

Accepted Answer

Distribute incoming requests across multiple servers

Answer

Store session data

Answer

Encrypt database records

Answer

Compile application code

Question 4

Which caching strategy writes to the cache and database simultaneously?

Accepted Answer

Write-through

Answer

Write-back

Answer

Write-around

Answer

Cache-aside

Question 5

Database sharding refers to…

Accepted Answer

Horizontally partitioning data across multiple databases/nodes

Answer

Replicating the entire database to every node

Answer

Encrypting individual rows

Answer

Compressing tables

Question 6

What problem does a message queue (e.g., Kafka, RabbitMQ) primarily solve?

Accepted Answer

Decoupling producers from consumers and smoothing load spikes

Answer

Encrypting traffic

Answer

Rendering the UI

Answer

Replacing the primary database

Question 7

In an eventually consistent system…

Accepted Answer

Replicas converge to the same value over time, but reads may be stale briefly

Answer

All reads always return the latest write

Answer

Data is never consistent

Answer

Writes are rejected during partitions

Question 8

A CDN improves performance mainly by…

Accepted Answer

Caching static content at edge locations near users

Answer

Running application logic closer to the database

Answer

Sharding the database

Answer

Load balancing writes

Question 9

What is a good use of a read replica?

Accepted Answer

Serving read-heavy traffic to offload the primary database

Answer

Handling all writes to reduce primary load

Answer

Storing backups only

Answer

Enforcing ACID across regions

Question 10

Idempotency in API design means…

Accepted Answer

Making the same request multiple times has the same effect as making it once

Answer

Requests must be encrypted

Answer

Every request returns cached data

Answer

Requests execute in parallel