Azure-to-Azure VM Replication Flow

1. Site Recovery Mobility Service Installation

   • When replication is enabled for an Azure VM, the Site Recovery Mobility Service extension is automatically installed on the VM.

   • This service registers the VM with Azure Site Recovery.

   • Continuous replication begins, capturing disk writes in real time and transferring them to a cache storage account in the source region.

2. Data Processing and Transfer

   • The cached data is processed by Site Recovery and then sent to the target Azure region.

   • The data can be stored either:

     • On replica managed disks, or

     • In a target storage account for the replicated VM.

3. Recovery Point Creation

   • Crash-consistent recovery points: Captures disk state at a point in time; generated every 5 minutes.

   • App-consistent recovery points: Captures disk data plus in-memory transactions and application state; generated according to the replication policy.

4. Failover and Failback

   • When you trigger a failover, Azure creates VMs in the target resource group, target virtual network, target subnet, and target availability set.

   • You can choose any recovery point for the failover.

   • After the primary region is back online, you can fail back to the original region.

Key Features of Azure-to-Azure Replication

• Automatic installation of required agents.

• Continuous replication with low RPO (Recovery Point Objective).

• Crash-consistent & app-consistent snapshots for flexible recovery.

• Seamless failover and failback across regions.

• No need for a secondary datacenter; Azure handles replication infrastructure.