Links: 101 AWS SAA Index
RPO and RTO¶
- RPO → Recovery Point Objective
- It is basically how often you run backups, how back in time can you recover.
- RPO is how much of data loss are you willing to accept in case of a disaster.
- RTO → Recovery Time Objective
- Defines the down time after disaster.
- RPO and RTO visualised
Our target is to decrease the RTO and RPO
- Cost increases as the try to decrease RTO and RPO.
- List of strategies with RPO and RTO in decreasing order.
- Backup & Restore: RPO and RTO in hours.
- It is quite cheap. We recreate infrastructure only when we have a disaster.
- Very easy.
- Pilot Light: RPO in minutes, RTO in hours.
- A small version of the app is always running in the cloud.
- Useful for the critical core (pilot light)
- Faster than Backup and Restore as critical systems are already up
- For example in the RDS will be running but not the EC2 instances so if some disaster strikes the on premise data centre then Route53 will manage the failover.
- Warm Standby: RPO in seconds, RTO in minutes.
- Full system is up and running, but at minimum size
- Upon disaster, we can scale to production load
- Multi Site/ Hot Site approach: RPO and RTO is almost 0.
- Full Production Scale is running AWS and On Premise
To remember RPO and RTO RPO decreases first, left hand side since P < T so RPO < RTO.
Last updated: 2022-05-01