Scaling

• Suppose you deployed your website and it becomes popular. You realize that your site can’t effectively manage all the requests it’s receiving. To solve the problem, you’ll need to increase the server’s hardware capacity.
• Scale refers to adding network bandwidth, memory, storage, or compute power to achieve better performance.
• 📝 Dynamic scalability architecture is an architectural model based on a system of predefined scaling conditions that trigger the dynamic allocation of IT resources from resource pools

Scaling up /down or vertical scaling

• Increase (up) or decrease (down) the memory, storage, or compute power on an existing virtual machine.
• E.g. add additional memory to a web or database server to make it run faster.

Scaling out/in or horizontal scaling

• Add (out) or remove (in) virtual machines to power your application.
• E.g., create many virtual machines configured in exactly the same way and use a load balancer to distribute work across them.

Scale down or scale in

• Do if you needed to scale up or scale out only temporarily.
• Help you save money.
• Services that help you optimize cloud spend:
  • Azure Advisor, Azure Cost Management
  • You can use these to identify where you’re using more than you need
    • and then scale back to the capacity you’re actually using.
  • See also Cloud Economics - Cost Optimization Best Practices