Site Recovery

Azure Site Recovery (ASR) is a subscription-based service that helps organizations use Azure infrastructure to establish disaster recovery (DR) for VM-based workloads. It works between an on-premises site and Azure or between two Azure regions. ASR replicates machines or VMs from one site to another and can monitor service availability and orchestrate recovery in the event of a service outage or a disaster. The service has supported replication of VMs between on-premises sites, but that scenario is no longer supported as of Mar. 1, 2023.

Service Overview

Disaster recovery focuses on establishing and maintaining backup infrastructure that allows a business to recover in the case of a significant outage, such as the catastrophic loss of a datacenter (either in Azure or on-premises), and continue to operate until the primary site is restored or a new primary site can be established.

ASR offers DR for the VMs or physical servers at one site by replicating disks and VM configurations to Azure. When the primary site suffers an outage, the organization can restore their systems in Azure on VMs using the replicated disks and configurations, typically called a failover. Failover operations do not occur automatically; in its current form, ASR requires an administrator to initiate failover. ASR can protect any of the following on-premises: physical servers, Hyper-V VMs, or VMware VMs; Microsoft-hosted Azure VMs; and VMs running on Azure Stack Hub and Stack HCI. Servers and VMs can be running Windows Server or Linux. For on-premises operations, ASR uses a VM-based virtual appliance to manage the replication process.