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Veeam Backup & Replication 9.5
User Guide for Microsoft Hyper-V

Off-Host Backup Proxy

By default, when you perform backup and replication jobs in the Hyper-V environment, VM data is processed directly on the source Hyper-V host where VMs reside, and then moved to the target, bypassing the backup server.

VM data processing can produce unwanted overhead on the production Hyper-V host and impact performance of VMs running on this host. To take data processing off the production Hyper-V host, you can use the off-host backup mode.

The off-host mode shifts the backup and replication load to a dedicated machine — an off-host backup proxy. The off-host backup proxy functions as a “data mover” which retrieves VM data from the source datastore, processes it and transfers to the destination.

The machine performing the role of an off-host backup proxy must meet the following requirements:

  • The role of an off-host backup proxy can be assigned only to a physical machine.

For evaluation and testing purposes, you can assign the off-host backup proxy role to a VM. To do this, you must enable the Hyper-V role on this VM (use nested virtualization). However, it is not recommended that you use such off-host backup proxies in the production environment. For more information, see or However, it is not recommended that you use virtualized off-host backup proxies in the production environment.

  • The source Microsoft Hyper-V host and the off-host backup proxy must be connected to the shared storage through a SAN configuration.
  • To create and manage volume shadow copies on the shared storage, you must install and properly configure a VSS hardware provider that supports transportable shadow copies on the off-host proxy and the Microsoft Hyper-V host. Typically, when configuring a VSS hardware provider, you need to specify a server controlling the LUN and disk array credentials to provide access to the array.

The VSS hardware provider is usually distributed as a part of client components supplied by the storage vendor. Any VSS hardware provider certified by Microsoft is supported. Some storage vendors may require additional software and licensing to work with transportable shadow copies.

  • If you back up or replicate VMs whose disks reside on a CSV with Data Deduplication enabled, make sure that you use a Microsoft Windows Server 2012 R2 or Microsoft Windows Server 2016 machine as an off-host backup proxy and enable the Data Deduplication option on this off-host backup proxy. Otherwise, off-host backup will fail.

For more information on required configuration, see System Requirements.

When you assign the role of an off-host backup proxy to the selected machine, Veeam Backup & Replication automatically installs on it light-weight components and services required for backup proxy functioning. Unlike the backup server, backup proxies do not require a dedicated SQL database — all settings are stored centrally, within the configuration database used by Veeam Backup & Replication.

To enable a Hyper-V host or a Windows machine to act as an off-host backup proxy, Veeam Backup & Replication installs the following services on it:

  • Veeam Installer Service is an auxiliary service that is installed and started on any Windows (or Hyper-V) server once it is added to the list of managed servers in the Veeam Backup & Replication console. This service analyzes the system, installs and upgrades necessary components and services.
  • Veeam Transport is responsible for deploying and coordinating executable modules that act as "data movers" and perform main job activities on behalf of Veeam Backup & Replication, such as performing data deduplication, compression and so on.
  • Veeam Hyper-V Integration Service is responsible for communicating with the VSS framework during backup, replication and other jobs, and performing recovery tasks. The service also deploys a driver that handles changed block tracking for Hyper-V.

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