Why Do We Need Regions and Availability Zones?

Why do we need Regions and Zones?

Let’s first understand that with a simple scenario.

Step 1: Single Data Center

Scenario: Imagine that your application is deployed in a data center in London.

What would be the challenges?

• Challenge 1: Slow access for users from other parts of the world (high latency)
• Challenge 2: What if the data center crashes?
  • Your application goes down (low availability)

Step 2: Multiple Data Centers in London

Let’s add in one more data center in London.

What would be the challenges now?

• Challenge 1: Slow access for users from other parts of the world
• Challenge 2 (SOLVED): What if one data center crashes?
  • Your application is still available from the other data center
• Challenge 3: What if the entire regionof London is unavailable?
  • Your application goes down

Step 3: Multiple Regions

Let’s add a new region: Mumbai.

What would be the challenges?

• Challenge 1 (PARTLY SOLVED): Slow access for users from other parts of the world
  • You can solve this by adding deployments for your applications in other regions
• Challenge 2 (SOLVED): What if one data center crashes?
  • Your application is still live from the other data centers
• Challenge 3 (SOLVED): What if the entire region of London is unavailable?
  • Your application is served from Mumbai

Regions

Imagine setting up your own data centers in different regions around the world. That’s not easy unless you are a big corporate!

AWS provides 20+ regions around the world (expanding every year).

Advantages of Regions include:

• High Availability
• Low Latency
• Adhere to government regulations

You can choose the right region(s) for your application based on:

• Where are your users located?
• Where is your data located?
• Regulatory and security compliance needs

AWS Availability Zones

Availability Zones are Isolated locations in a Region.

Each AWS Region has at least two Availability Zones.

Availability Zones increase the availability of applications in the same region.

AWS Regions and Availability Zones Examples

New Regions and AZs are constantly added. Here is a table showing examples of regions and AZs.