Azure provides Azure Site Recovery (ASR) service for disaster recovery of Azure Virtual Machines.
When you setup disaster recovery using Azure Site Recovery, Azure VMs continously replicate to a different secondary region. If an outage happens on the primary region, then you can fail over to the secondary region and access the VMs from that location. After the outage recovers, you can fail back to the primary location again.
Following are the different components that have to be considered for disaster recovery of Azure Virtual Machines
1. Virtual Machines - One or more virtual machines that have to be setup for disaster recovery.
Storage - Storage accounts attached to the Virtual Machines
Network components - One or more Subnets in a Vnet, within which the virtual machines are located.
Cache store account - Cache storage account on the source side that is used for replication.
Target resources - Target resources to which the data is replicated.