Please note that ISO 27001 does not prescribe how far apart a data center and a disaster recovery site should be.
Additionally, most regulations and industry practices also do not define any specific distance to recovery sites, because many factors can affect what would be considered a “safe” distance (e.g., type of disaster, access to public services, risk level, etc.). From our experience, we suggest you start a discussion suggesting a distance between 30 miles (50 kilometers) and 100 miles (160 kilometers) away from your primary location, and from that analyze your organization's context (a geographic situation, available resources, required investment, etc.).
This article will provide you with a further explanation of the distance of the recovery site:
This material will also help you regarding the distance of the recovery site: