An Azure native disaster recovery service. Previously known as Microsoft Azure Hyper-V Recovery Manager.
For physical or VMware machines that have failed over to Azure using Azure Site Recovery, failback is supported only to VMware virtual machines, not directly to physical servers or to Hyper‑V.
Key points from the supported flow:
- Physical servers replicated to Azure can only fail back as VMware VMs
- A VMware infrastructure is required on‑premises to perform failback.
- This is explicitly called out in the failback preparation guidance: physical servers replicated to Azure using Site Recovery can only fail back as VMware VMs.
- Why the Fail back option is greyed out
- Failback depends on:
- An on‑premises configuration server that knows about the original machine.
- A master target server and vCenter/ESXi environment that meet the VMware failback requirements.
- If the configuration server, master target, vCenter, or required discovery is not in place or not connected, failback will not be available and options will appear disabled.
- Additionally, there are explicit scenarios where failback is not possible, including:
- Using ESXi 5.5 free edition or vSphere 6 Hypervisor free edition.
- Certain OS versions (for example, Windows Server 2008 R2 SP1 physical server).
- VMs that have been migrated or moved to another resource group.
- Replica Azure VM deleted or not protected back to on‑premises.
- Failback depends on:
- Required components for failback
To see and use failback, the following must be in place and healthy:
- On‑premises configuration server running and connected to Azure.
- On‑premises master target server (VMware) and process server configured per the VMware failback preparation article.
- Site‑to‑site VPN or ExpressRoute private peering between Azure and on‑premises for failback traffic.
- vCenter Server connected and discovered with appropriate permissions so datastores and VMs are visible.
- No snapshots on the master target server VMs.
- Correct UUID configuration and no UUID clashes if templates were used.
- Original vs alternate location recovery
- Original Location Recovery (OLR): fail back to the same on‑premises VMware VM if it still exists and its datastore is accessible to the master target host.
- Alternate location recovery: if the original VM does not exist, fail back to a new VMware VM on a datastore accessible to the master target.
- Failback is only supported to the original vCenter and configuration server; a new configuration server or new vCenter cannot be used for failback of existing Azure replicas.
- How this relates to a Hyper‑V migration
- ASR’s physical/VMware‑to‑Azure scenario does not support direct failback to Hyper‑V or to bare‑metal physical servers.
- To move workloads ultimately to Hyper‑V, a typical pattern is:
- Use ASR for DR between on‑premises VMware/physical and Azure.
- Fail back from Azure to VMware (supported path).
- Perform a separate migration from VMware to Hyper‑V (outside ASR’s physical/VMware failback flow).
- High‑level failback sequence once prerequisites are met
- Prepare for reprotection and failback:
- Ensure configuration server, master target, vCenter, connectivity, and permissions are correct.
- Remove snapshots and resolve any unsupported scenarios listed in the documentation.
- Reprotect Azure VMs to on‑premises (Azure → on‑premises direction) so data starts replicating back.
- When replication is healthy, run failover from Azure to on‑premises (planned/unplanned as appropriate), choosing the desired recovery point.
- Commit the failover to finalize and remove the Azure replicas.
- Prepare for reprotection and failback:
Because of these platform constraints, failing a VM over to Azure and then directly restoring it to a new physical server or to Hyper‑V is not supported with this ASR scenario; failback targets must be VMware VMs managed through the supported VMware/physical‑to‑Azure failback path.
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