RTO stands for Recovery Time Objective. RTO is the objective (requiremented amount of) time that you need to recover your organisation by after a disaster.
In other words, the RTO is the amount of time your organisation needs to be able to be back up and running after a system goes down. The RTO will be different from service to service across your organisation.
You need to select a backup solution that enables you to restore your services (note that RTO is based on services, rather than computers) in the amount of time that the business requires. You should also factor any dependancies into the RTO calculation.
❗ Note: The RTO might be different at different times of the day.
For example, your organisation may say that they can only go without email for 30 minutes during office hours, but can go without email all night.
In the above example, you will need to design a backup solution (which includes a process and perhaps monitoring) that enables IT staff to be able to respond in the correct timeframe and have the email service back up and running within 30 minutes during the day. This includes any dependant systems, such as Active Directory and network switches. Your solution may also include a monitoring solution that alerts engineers that there is a problem with email so that they can ensure they start the restore process in a timely fasion that enables them to meet the RTO SLA. There may also be a process in the design that says that engineers don’t have to respond out of hours, before a particular time in the morning.
When you are designing a backup solution to achieve a specific RTO, you may need to negotiate RTO with the business. For example, the business may say that it costs $5000 an hour to have an outage to a particular service so they want an RTO of 1 hour. You may then come back to the business with a design that achieves that RTO, but costs $1,000,000. This may then change the businesses cost-value perception on the 1 hour RTO and then increase this to a 6 hour RTO. 🙂
Once you’ve agreed the RTO with the business, get the service stakeholder to sign off on this to agree the RTO and store the document somewhere safe.
Don’t forget to consider RPO when designing your backup solution.