📈 The Need for Scaling - Vertical vs Horizontal 관련

Load Balancing with Azure Application Gateway and Azure Load Balancer - When to Use Each One

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You’ve probably heard someone mention load balancing when talking about cloud apps. Maybe even names like Azure Load Balancer, Azure Application Gateway, or something about Virtual Machines and Scale Sets. 😵‍💫 It all sounds important...but also a l...

• So, What Do You Do When One Server Isn’t Enough?
  • 🧱 Option 1: Vertical Scaling (aka Scaling Up)
  • 🧩 Option 2: Horizontal Scaling (aka Scaling Out)
• Quick Real-World Example
  • So, remember 👇🏾

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Load Balancing with Azure Application Gateway and Azure Load Balancer - When to Use Each One

You’ve probably heard someone mention load balancing when talking about cloud apps. Maybe even names like Azure Load Balancer, Azure Application Gateway, or something about Virtual Machines and Scale Sets. 😵‍💫 It all sounds important...but also a l...

Imagine your app is growing. At first, it’s just a few users. Then a few hundred. Then thousands are logging in, placing orders, chatting, uploading photos - all at once 😮

Suddenly, your server (VM) is under pressure. It’s like trying to pour a flood through a straw.

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So, What Do You Do When One Server Isn’t Enough?

This is where scaling comes in - the art of upgrading your app’s infrastructure to keep up with traffic.

There are two main ways to scale:

🧱 Option 1: Vertical Scaling (aka Scaling Up)

You take your existing VM and give it more power:

• Add more CPUs 🧠
• Increase RAM 🧵
• Add faster disks ⚡

Think of it like upgrading from a regular car to a sports car. It’s the same vehicle, just faster and stronger.

Pros

• Simple to do
• No major changes to your app setup

Cons

• There’s a limit to how much you can upgrade
• Still a single point of failure: if the VM crashes, everything goes down 😬

🧩 Option 2: Horizontal Scaling (aka Scaling Out)

Instead of boosting one server, you add more servers - multiple VMs running copies of your app.

Now:

• Users can be distributed across all these VMs
• If one goes down, others keep serving traffic
• You can dynamically add or remove VMs based on traffic

It’s like opening more checkout counters in a busy supermarket 🛒

Pros

• The load is evenly distributed. For example, if one server previously handled 100% of the traffic, adding two more servers would result in the traffic being split into approximately 33% to 34% for each server.
• Improves both performance and reliability
• You can scale based on real-time demand, that is traffic inflow

Cons

• Needs something to split traffic between VMs - Load Balancers
• More expensive. You end up paying the original amount for 1 VM (for example $30) for the number of VMs you provide - if you provide 3 VMs at $30 each, you end up paying $90 at the end of the month

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Quick Real-World Example

Let’s say you’ve launched an e-commerce site for sneakers 👟 Traffic spikes during a big sale? Your vertical scaling (bigger VM) might choke.

But with horizontal scaling:

• You spin up 5 VMs across different regions
• Traffic is shared between them
• If one VM slows down, others handle the load

So, remember 👇🏾

Scaling Type	Description	Pros	Cons
🧱 Vertical Scaling	Make 1 VM more powerful (adding more CPU power, SSD, RAM, bandwidth, and so on)	Easy setup, fewer changes	Hardware limits, 1 point of failure - If that 1 server/VM goes down, so does your app
🧩 Horizontal Scaling	Add more VMs to handle traffic	Flexible, reliable	Needs traffic distribution logic (Load Balancer). Usually more expensive (the price of 1 VM times the number of VMs)