What are RPO and RTO in backup planning and how to calculate them?

The concepts of RPO and RTO are key metrics when developing a disaster recovery strategy and planning backups in any modern IT infrastructure. Without a clear understanding of these indicators, it is impossible to choose the right backup frequency and data storage architecture.

The RPO metric stands for Recovery Point Objective. It defines the maximum acceptable amount of data that an organization can afford to lose as a result of a failure, measured in a time equivalent. For example, if the RPO is four hours, it means that the system must store data so that in the event of a disaster, no more than the last four hours of work is lost.

The RTO metric stands for Recovery Time Objective and indicates how long it may take to fully restore the system to working order after a failure occurs. This includes the time to detect the problem, select the required backup version, download it, unpack it, and directly deploy it on hardware or in the cloud.

To calculate these metrics, it is necessary to conduct an audit of business processes and assess financial losses from downtime of each specific service. Mission-critical financial systems typically require RPO and RTO approaching zero or a few minutes, which is achieved through mirroring and clustering. For less important internal archives, these indicators can be a day or more.

To ensure the specified RPO and RTO values in practice, administrators configure combined copy creation schemes. For example, to meet a strict RPO, they use continuous transaction replication, and to meet RTO, they keep pre-configured virtual machine images ready to run. Regular recovery testing helps ensure that real metrics meet planned business requirements.