04. Tradeoffs to consider

You can build a system that is singular with no failover options, and you can build systems that are Multi-AZ, Multi-Region with automated lightning fast failover. It is up to you to first determine what level of redundancy is appropriate and then figure out how to build that system.

When approaching a new product or service, you should consider how important the system will be. Will the existence of the company depend on it staying up, or is it just helping a team vote on lunch choices? Will it bring in 10 million dollars a month, or is it providing a service for free? Ultimately, there are tradeoffs that need to be considered, and understanding them is key to understanding how resilient to make a system.

ND0063 C1 L2 03 Developing Your Intuition About Resiliency Video

Not all AWS services are redundant by default. Some services have varying degrees of redundancy and it usually costs more to make a service redundant.

Considerations

What should you consider when determining how resilient a system needs to be?
SOLUTION:
  • Cost
  • SLAs
  • How critical the system is to your users

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