Why scalability handles growing traffic in HLD - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define scalability as the system's ability to handle {{BLANK_1}} traffic.

HLD

Scalability means a system can handle [1] traffic without performance loss.

Drag options to blanks, or click blank then click option'

Arandom

Bgrowing

Cdecreasing

Dconstant

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing constant traffic, which does not reflect growth.

Scalability is about handling growing traffic smoothly.

2fill in blank

medium

Complete the code to show that scalability can be achieved by adding more {{BLANK_1}}.

HLD

To improve scalability, we add more [1] to distribute the load.

Drag options to blanks, or click blank then click option'

Aservers

Busers

Cdatabases

Derrors

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing users or errors, which do not help handle traffic.

Adding more servers helps distribute traffic and improve scalability.

3fill in blank

hard

Fix the error in the statement about scalability: 'Scalability means the system can handle {{BLANK_1}} traffic by adding a single server.'

HLD

Scalability means the system can handle [1] traffic by adding a single server.

Drag options to blanks, or click blank then click option'

Aconstant

Bdecreasing

Cgrowing

Drandom

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing constant or decreasing traffic, which do not reflect scalability.

Scalability is about handling growing traffic, not just constant or decreasing.

4fill in blank

hard

Fill both blanks to complete the scalability strategy: 'Use {{BLANK_1}} to balance load and {{BLANK_2}} to add capacity.'

HLD

Use [1] to balance load and [2] to add capacity.

Drag options to blanks, or click blank then click option'

Aload balancers

Bcaches

Cmore servers

Ddatabases

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing caches or databases which do not directly add capacity or balance load.

Load balancers distribute traffic, and more servers increase capacity for scalability.

5fill in blank

hard

Fill all three blanks to complete the scalability explanation: 'Scalability involves {{BLANK_1}} servers, {{BLANK_2}} data storage, and {{BLANK_3}} traffic efficiently.'

HLD

Scalability involves [1] servers, [2] data storage, and [3] traffic efficiently.

Drag options to blanks, or click blank then click option'

Aadding

Bdistributing

Cbalancing

Dreducing

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing reducing, which is opposite of scalability goals.

Scalability means adding servers, distributing data storage, and balancing traffic efficiently.

Practice

1. What does scalability in system design primarily help with?

easy

A. Handling more users and traffic smoothly

B. Reducing the number of servers

C. Making the system slower

D. Limiting the system to one user

Solution

1. Step 1: Understand the meaning of scalability

   Scalability means the system can grow to handle more users or traffic without problems.

2. Step 2: Identify the main goal of scalability

   The main goal is to manage increasing traffic smoothly, not to reduce servers or slow down.

3. Final Answer:

   Handling more users and traffic smoothly -> Option A

4. Quick Check:

   Scalability = Handling more traffic [OK]

Hint: Scalability means growing capacity to handle more users [OK]

Common Mistakes:

• Thinking scalability reduces servers
• Confusing scalability with slowing system
• Believing scalability limits users

2. Which option correctly describes vertical scaling?

easy

A. Upgrading the hardware of a single machine

B. Distributing traffic using load balancers

C. Adding more machines to the system

D. Reducing the number of users

Solution

1. Step 1: Define vertical scaling

   Vertical scaling means improving one machine's hardware, like adding CPU or memory.

2. Step 2: Differentiate from other options

   Adding machines is horizontal scaling; load balancers distribute traffic; reducing users is unrelated.

3. Final Answer:

   Upgrading the hardware of a single machine -> Option A

4. Quick Check:

   Vertical scaling = Upgrade one machine [OK]

Hint: Vertical scaling upgrades one machine's hardware [OK]

Common Mistakes:

• Confusing vertical with horizontal scaling
• Thinking vertical scaling adds machines
• Mixing load balancers with scaling types

3. Consider a system with 3 servers behind a load balancer. If traffic doubles, what happens when horizontal scaling is applied?

medium

A. Remove servers to reduce complexity

B. Upgrade the CPU of one server only

C. Add more servers to share the load

D. Ignore traffic increase and keep same setup

Solution

1. Step 1: Understand horizontal scaling

   Horizontal scaling means adding more servers to handle increased traffic.

2. Step 2: Apply to the scenario

   With doubled traffic, adding servers helps share load; upgrading one server is vertical scaling.

3. Final Answer:

   Add more servers to share the load -> Option C

4. Quick Check:

   Horizontal scaling = Add servers [OK]

Hint: Horizontal scaling means adding servers [OK]

Common Mistakes:

• Choosing to upgrade one server (vertical scaling)
• Removing servers when traffic grows
• Ignoring traffic increase

4. A system uses a load balancer but still crashes under high traffic. What is the likely issue?

medium

A. Too many servers are added unnecessarily

B. Load balancer is not distributing traffic evenly

C. Vertical scaling was applied correctly

D. Traffic is decreasing, causing overload

Solution

1. Step 1: Analyze load balancer role

   Load balancers distribute traffic evenly to servers to prevent overload.

2. Step 2: Identify cause of crash

   If system crashes despite load balancer, it may not be distributing traffic properly, causing some servers to overload.

3. Final Answer:

   Load balancer is not distributing traffic evenly -> Option B

4. Quick Check:

   Uneven load distribution causes crashes [OK]

Hint: Check if load balancer spreads traffic evenly [OK]

Common Mistakes:

• Assuming too many servers cause crash
• Thinking vertical scaling always fixes crashes
• Believing traffic decrease causes overload

5. A web app faces sudden traffic spikes. Which combination best ensures smooth scaling?

hard

A. Only upgrade one server's CPU and RAM

B. Limit user access to reduce traffic

C. Remove load balancers and rely on a single powerful server

D. Use horizontal scaling with load balancers and auto-scaling groups

Solution

1. Step 1: Identify best scaling approach for spikes

   Horizontal scaling with load balancers allows adding/removing servers dynamically to handle spikes.

2. Step 2: Evaluate other options

   Upgrading one server limits capacity; removing load balancers causes bottlenecks; limiting users reduces usability.

3. Final Answer:

   Use horizontal scaling with load balancers and auto-scaling groups -> Option D

4. Quick Check:

   Horizontal scaling + load balancers = smooth spikes [OK]

Hint: Combine horizontal scaling and load balancers for spikes [OK]

Common Mistakes:

• Relying only on vertical scaling
• Removing load balancers causing bottlenecks
• Limiting users instead of scaling