What are RPO and RTO, and what is the difference between them? DevOps interview question.

Questions about RPO (Recovery Point Objective) and RTO (Recovery Time Objective) are often asked in DevOps and IT interviews.

In this short article, I will explain what RPO and RTO are and what is the difference between the two terms.

Both RPO and RTO are part of the disaster recovery terminology.

RPO (Recovery Point Objective): acceptable data loss or how much data loss your application can allow in case of disaster.

RTO (Recovery Time Objective): acceptable downtime, or measure how quickly, after a failure, the application must be available again.

Imagine you did a backup of your data at 13:00. Unfortunately, the server with your data burned down at 16:00, and you need to recover the last backup on a new server now.

It took 1 hour to install the new server and restore data from the backup, everything was up and running by 17:00.

Based on the example, you lost 3 hours of data because you did the last backup at 13:00. The server wasn’t available for an hour.

So the RPO in this example is 3 hours (which is a lot, not realistic time), and the RTO is one hour.

That means if the company policy allows 10 minutes of RPO, you need to back up data every 10 minutes.

For the RTO, the IT department must have clear instructions on how to act in a disaster situation (RTO Policies and Procedures). Who does what, what scripts and backups need to be prepared, in what sequence to run the procedures, etc.

As you see, the answer to the RPO/RTO interview question is pretty simple, despite the fact that the procedure itself can be very complex and requires clear guidelines and instructions.