Everything comes at a price

HA architecture is driven by your requirements.
An HA, multi-AZ, fault tolerance infrastructure is possible, however it comes at a price.

Non-HA Environment	HA Environment
Server 1	Server1 Server 2 Loadbalancer

RTO & RPO

RTO (Recovery Time Objective) is the amount of time it takes you to recover your business operations after a disaster strikes
- Example:
  - If RTO is 3 hours, then one needs to invest the funds required to make sure a DR region is always ready in case the main region goes down due to disaster.
RPO (Recovery Point Objective) is concerned with data and maximum tolerance period to which data can be lost.
- This helps to determine how well we should design the infrastructure.
- Example:
  - If RPO is 5 hours for a database, then you should backup the database every 5 hours.

RTO is a broader scope and covers the whole business and systems.
RPO is more directly related to the interval of backup to take to avoid data loss.