Testing and Running Failover

A disaster recovery plan that has never been tested is just a hypothesis. Test failover lets you validate that your VMs boot correctly, applications start, and network connectivity works in the target region — all without disrupting the source environment or breaking ongoing replication. Many organisations discover their DR plans have gaps only when an actual disaster occurs, which is exactly when a broken plan causes maximum damage. Regular test failovers are a compliance requirement for most regulatory frameworks.

ASR supports three types of failover actions. Test failover creates copies of the failed-over VMs in an isolated network (you specify the target VNet) without affecting replication or the source environment. Planned failover is used for scheduled migrations or maintenance — it first syncs any remaining changes then shuts down the source before failing over. Unplanned failover (used during a real disaster) fails over immediately from the latest recovery point without waiting for a final sync.