Backup Exec 20.6 Administrator's Guide

The Backup Exec Agent for Microsoft Hyper-V (Agent for Hyper-V) lets you back up and restore the following resources:

• Hyper-V hosts that run on supported versions of Microsoft Windows.

  You can find a list of supported operating systems, platforms, and applications in the Backup Exec Software Compatibility List.

• All virtual machines that reside locally on the Hyper-V hosts.

• Clustered Hyper-V hosts, including the virtual machines that reside on cluster shared volumes (CSV).

• The virtual machines that have their disks hosted on Server message block (SMB).

• The virtual machines that have their disks hosted on Scale-Out File Server.

• The Resilient Change Tracking (RCT) method: This method is available for the virtual machines that are hosted on Microsoft Hyper-V Server 2016 or later and have configuration version of 8.0 or later. RCT is a native Microsoft Hyper-V mechanism for tracking changed blocks in the virtual hard disks of a virtual machine. During backup, Backup Exec requests Microsoft Hyper-V to create a checkpoint for the selected virtual machine. The backup is done for this checkpoint.

  After the virtual machine backup, before the checkpoint is merged with the base virtual machine disk, Hyper-V converts the checkpoint to a reference point. The reference point represents the point-in-time view of the virtual machine disk state.

  During the incremental backup of the same virtual machine, Backup Exec creates a new checkpoint and uses it as a source for the backup. Backup Exec queries Hyper-V to get the incremental changes between the reference point created during the previous run and the checkpoint created during the current run of the backup job. Only the changed data blocks are backed up from the created checkpoint.

  Backup Exec supports both incremental backup and differential backup using the RCT method.

• The standard processing method: This method reads the whole virtual disk and identifies the changes that should be backed up. The changed blocks that are identified are then backed up. Backup Exec supports both incremental backup and differential backup using this method.

• The faster processing method: This method is faster than the standard processing method because it writes all changes to a new differencing disk that is backed up. Backup Exec supports only incremental backup using this method. To configure Hyper-V incremental and differential backup settings please refer to the 'Configuring default backup settings' section.

The amount of downtime for a saved state backup job depends on the following:

• The amount of memory that is allocated to the virtual machine.

• The current load on the host's operating system.