Why infrastructure design underpins everything in HLD - Challenge Your Understanding

Challenge - 5 Problems

🧠 Conceptual

intermediate

Why is infrastructure design critical for system reliability?

Consider a web application that experiences frequent downtime. Which infrastructure design aspect most directly improves its reliability?

A Implementing redundant servers and failover mechanisms

B Reducing the number of users accessing the system

C Deploying the application only on a local machine

D Using a single powerful server with high CPU and memory

💡 Hint

Think about how to keep the system running even if one part fails.

Redundancy and failover ensure that if one server fails, others take over, improving reliability.

❓ Architecture

intermediate

Which infrastructure design best supports scalability?

You expect your system's user base to grow rapidly. Which infrastructure design choice best supports this growth?

A Using horizontal scaling with load balancers and multiple servers

B Limiting the number of concurrent users

C Designing a monolithic server that handles all requests

D Deploying the system on a single cloud instance

💡 Hint

Think about adding more machines to handle more users.

Horizontal scaling with load balancers distributes traffic across servers, allowing growth.

❓ scaling

advanced

What is the main tradeoff when choosing between vertical and horizontal scaling?

When designing infrastructure, what is the primary tradeoff between vertical scaling (upgrading a single server) and horizontal scaling (adding more servers)?

A Vertical scaling eliminates downtime; horizontal scaling increases downtime

B Vertical scaling requires more servers; horizontal scaling requires fewer servers

C Vertical scaling improves network speed; horizontal scaling reduces CPU usage

D Vertical scaling is cheaper but less flexible; horizontal scaling is more complex but more scalable

💡 Hint

Consider cost, complexity, and flexibility.

Vertical scaling upgrades one server, cheaper but limited; horizontal scaling adds servers, more complex but scales better.

❓ tradeoff

advanced

Which infrastructure design choice impacts system latency the most?

To reduce latency for users worldwide, which infrastructure design choice is most effective?

A Increasing the CPU speed of the central server

B Using a single central data center for all users

C Deploying servers in multiple geographic regions (edge locations)

D Reducing the number of database queries

💡 Hint

Think about physical distance between users and servers.

Deploying servers closer to users reduces network travel time, lowering latency.

❓ estimation

expert

Estimate the infrastructure capacity needed for 1 million daily active users

Your system expects 1 million daily active users, each making an average of 10 requests per day. Each server can handle 10 requests per second. Estimate the minimum number of servers needed to handle peak load assuming peak traffic is 10% of daily requests concentrated in one hour.

A 12 servers

B 28 servers

C 60 servers

D 36 servers

💡 Hint

Calculate total requests per peak hour, then divide by server capacity.

1 million users * 10 requests = 10 million requests/day. Peak 10% in 1 hour = 1 million requests in 3600 seconds ≈ 278 requests/sec. Each server handles 10 requests/sec, so servers needed ≈ 278 / 10 = 28 servers.