Throughput, latency, and availability in HLD - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is throughput in system design?

Throughput is the amount of work or number of tasks a system can complete in a given time, like how many requests a server can handle per second.

beginner

Define latency in the context of system performance.

Latency is the time delay between sending a request and receiving a response, similar to how long it takes for a letter to arrive after mailing it.

beginner

What does availability mean in system design?

Availability is the percentage of time a system is operational and accessible, like a store being open for customers most of the day.

intermediate

How are throughput and latency related but different?

Throughput measures how many tasks a system can do over time, while latency measures how fast each individual task is completed. A system can have high throughput but also high latency if tasks queue up.

beginner

Why is high availability important for user experience?

High availability ensures users can access the system whenever they need it, preventing frustration and loss of trust, much like a reliable service that is always open when customers want it.

What does throughput measure in a system?

A Percentage of uptime

B Time delay for a single task

C Number of tasks completed per unit time

D Amount of data stored

Throughput is about how many tasks or requests a system can handle in a given time.

Latency is best described as:

A Total tasks completed per second

B Time taken to respond to a single request

C System uptime percentage

D Number of users connected

Latency measures the delay between sending a request and receiving a response.

Which metric indicates how often a system is operational?

A Latency

B Throughput

C Bandwidth

D Availability

Availability shows the percentage of time the system is up and running.

If a system has high throughput but high latency, what does it mean?

A It processes many tasks but each takes a long time

B It processes few tasks quickly

C It is often down

D It has low capacity

High throughput with high latency means many tasks are done overall, but each task waits longer.

Why is availability critical for online services?

A It ensures users can access the service anytime

B It increases throughput

C It reduces latency

D It stores more data

Availability ensures the service is accessible whenever users need it.

Explain throughput, latency, and availability using a real-life example.

Think about how a busy store works and how fast customers get served.

How do throughput, latency, and availability impact user experience in a web application?

Consider what happens if a website is slow, busy, or down.