IoT hub is a PaaS service from Azure. Customers and users do not directly interact with underlying number and size of virtual machines on which IoT hub service is running. Users decide on the region, the Sku of the IoT hub and number of units for their application. The rest of the configuration is determined and executed by Azure behind the scenes. Azure ensures that every PaaS service is highly available by default. It does so by ensuring that multiple virtual machines provisioned behind the service are on separate racks in the data center. It does this by placing those virtual machines on an availability set and on a separate fault and update domain. This helps in high availability for both planned as well as unplanned maintenance. Availability sets take care of high availability at data center level.
To achieve high availability across multiple data centers...