Look beyond the second server
Two web servers using one database can still depend on that database. I want you to trace the complete request path. Adding a second application instance does not solve every failure that could stop users from working.
Make remaining capacity usable
Plan how traffic avoids an unhealthy server, where sessions live and how the data layer handles failure. Use each service’s availability configuration deliberately. A diagram containing two Zones is a design proposal, not proof that recovery works.
Test the expected behaviour
Write a failure scenario and describe what users should experience. Test safely in a learning environment. Availability and disaster recovery have different objectives; decide the acceptable interruption and data loss before selecting additional infrastructure.
Try it yourself
Draw a two-Zone website with traffic entry, application and database. Mark every component that still has only one usable copy.
A common question
Is multi-AZ the same as multi-Region?
No. Availability Zones are within a Region. Multiple Regions introduce additional data and operating decisions.
References & video notes
Use the video to follow the topic with me. Console screens and older offers can change, so check the current AWS documentation before performing a lab.
Keep learning
- What is Amazon EC2? A beginner’s guide
- What is an AMI? Understanding EC2 machine images
- Plan and launch your first EC2 instance