On-Host Backup

During on-host backup, VM data is processed on the source Microsoft Hyper-V host where VMs that you want to back up or replicate reside. All processing operations are performed directly on the source host, which performs the role of the backup proxy. For this reason, on-host backup may result in high CPU usage and network overhead on the host system.


The described procedure applies to the backup process for Microsoft Hyper-V Server 2012 R2 and earlier. For more information about the backup of VMs registered on Microsoft Hyper-V 2016 and later versions, see Online Backup and Crash-Consistent Backup.

The on-host backup process is performed in the following way:

  1. Veeam Backup & Replication triggers a snapshot of the necessary volume.
  2. Veeam Data Mover on the host uses the created volume snapshot to retrieve VM data; it processes the VM data and copies it to the destination.
  3. After the backup process is complete, the volume snapshot is deleted.

On-Host Backup 

Assigning Role of On-Host Backup Proxy in CSV

If you back up or replicate VMs whose disks are located on a CSV in Microsoft Hyper-V Server 2012 or 2012 R2, and Microsoft CSV Software Shadow Copy Provider is used for snapshot creating, Veeam Backup & Replication assigns the role of an on-host backup proxy to the host owning the CSV. If VM disks are located on different CSVs, Veeam Backup & Replication may use several on-host backup proxies, which are the required hosts owning CSVs.


Veeam Backup & Replication cannot use an off-host proxy to selectively process the VHD on the array that supports hardware VSS snapshots and simultaneously use an on-host proxy to process another VHD located on a different array. Veeam Backup & Replication creates only one shadow copy for such VM (or a group of VMs) and cannot split it. In such a case, Veeam Backup & Replication will use an on-host backup proxy.

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Page updated 5/17/2024

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