For a company that offers online billing systems for their customers, which strategy ensures the RPO is kept as low as possible?

Cloud backup configured as a mirror continuously replicates data to the cloud, meaning the recovery point is always nearly current and potential data loss is reduced to seconds or less. For an online billing system where every transaction matters, this near-zero RPO is critical. Continuous mirroring ensures the replicated dataset matches the production state at all times, directly minimizing RPO.

Spare onsite disks address hardware availability and can improve RTO (Recovery Time Objective), but they do not replicate data and therefore have no effect on RPO.

Periodic snapshots capture data at scheduled intervals, so any data written between snapshots is lost in a failure, resulting in a higher RPO than continuous mirroring.

External storage backups are typically scheduled jobs with fixed backup windows, creating gaps between backup cycles that increase the potential data loss window and raise the RPO.