How does geographically distributed backup work and how to design it?

Geographically distributed backup involves creating and storing data copies across multiple data centers or regions remote from each other. The main goal of this approach is to ensure business continuity and protect information during large-scale emergencies, natural disasters, or regional cloud infrastructure outages when a local office or primary data center completely fails.

The design of such a system starts with analyzing RPO and RTO, which are the allowable data loss time and recovery time. Based on these parameters, the replication architecture is chosen: synchronous for critical databases with minimal data loss, or asynchronous for long-term archives. It is important to consider the bandwidth of communication channels between sites, as transferring large volumes of data can place a significant load on the network.

When organizing distributed storage, special attention must be paid to the security of network connections when transferring archives over the public internet. For this purpose, secure VPN tunnels and end-to-end data encryption are used even before sending data to the remote site. A traffic prioritization scheme should also be planned so that backups do not interfere with the operation of core business applications during peak hours.