Different methods

• Backup virtual machines (VMs) by installing the client in the VMs
• Backup and restore VMs using Windows Backup API
• Backup and restore VMs using Hyper-V client

Backup virtual machines (VMs) by installing the client in the VMs

Advantages:

• Equivalent setup to bare metal machines
• More fine grained backup configuration: You can combine image and file backups, exclude files from backup, more easily run commands before or after backup etc.

Disadvantages:

• Performance in VMs is slightly worse than bare metal performance. This also applies to backup software in the VM
• If there is no changed block tracking (CBT) driver installed it might be inefficient
• Separate setup/configuration for each VM. Need access to VM to install software on it
• VMs snapshot their storage themselves whereas it might be more efficient to let the Hyper-V VM storage (e.g. NetApp) handle the snapshotting (if present)

Conclusion: Preferred method if you already manage bare metal servers, have no problem installing software in the VMs or want have more fine grained backup configuration.

How to setup:

See 2.2 Client installation in the administration manual.

How to restore:

See 9 Restoring backups in the administration manual.

Backup and restore VMs using Windows Backup API

Advantages:

• Runs on the Hyper-V host, so no need to install and a setup client in each VM
• Your Hyper-V VM storage may support VSS (Volume Shadow Copy Service), so that the storage snapshots the VM (e.g. NetApp)
• Backup via the standard Windows Backup API
• Works with older Hyper-V versions (<2016)

Disadvantages:

• All your VMs get snapshotted and backed up all at once. You cannot have different backup frequencies for different VMs and because snapshots happen at volume level snapshot overhead is much larger if you have multiple VMs with IO
• If you do not have a changed block tracking (CBT) driver the client wiill have to read the whole virtual disks during each backup to find out what changed. The CBT driver works only with locally attached storage (not with remote storage or cluster shared volumes)

Conclusion: Only use if you have an old Hyper-V version (<2016) or if it is a necessity that you use the snapshot functionality of your VM storage.

How to setup:

Install the client on the Hyper-V host. Afterwards select “Configure components to backup” on the tray icon and configure the VMs to backup. You can also run cd "C:\Program Files\UrBackup" then UrBackupClientGUI.exe selectWindowsComponents in a command window to get this selection screen.

How to restore:

Select “Restore components” on the tray icon and choose the time and VMs to restore, then restore. You can also run cd "C:\Program Files\UrBackup" then UrBackupClientGUI.exe restoreWindowsComponents in a command window to get this restore screen.

Backup and restore VMs using Hyper-V client

Advantages:

• Runs on the Hyper-V host, so no need to install and setup a client in each VM
• Uses build-in Hyper-V Resilient Change Tracking (RCT) to track changes to VM disks
• Creates a virtual client for each VM, so each VM can be backed up with a different frequency
• Uses production checkpoints to snapshot each VM separately

Disadvantages:

• Does not work with Hyper-V versions before Hyper-V 2016
• Hyper-V creates and manages the snapshots itself whereas it might be more efficient to let the Hyper-V VM storage (e.g. NetApp) handle the snapshotting (if present)

Conclusion: Best method if you do not want to run a client in each VM and use Hyper-V >=2016

How to setup/restore:

See the Hyper-V client user manual