Hyper-V virtual machines
This section provides considerations and requirements for protecting Hyper-V environments.
Following is a summary of the high-level steps for backing up Hyper-V virtual machines. The information includes links to detailed instructions for each procedure.
Step 1: | Review Best practices and requirements for Hyper-V protection. |
Step 2: | Install the Unitrends Windows agent on your Hyper-V host. See Installing the Windows agent. |
Note: For most Windows servers, the appliance can push-install the agent when you add the asset. If you will be push-installing the agent, skip to Step 3:. For push-install requirements, see Windows agent requirements.
Step 3: | Add the Hyper-V host to your Unitrends appliance. See Adding a virtual host. |
Step 4: | Create backup jobs for your VMs: |
• | To create a job manually, see To create a Hyper-V backup job. |
• | To create a job by using an SLA policy, see To create an SLA policy for Hyper-V assets. |
• | For a comparison of the manual and SLA policy job creation methods, see About creating backup and backup copy jobs. |
Review the information in these topics before implementing Hyper-V host-level protection:
Follow these recommendations:
• | Adhere to Microsoft’s best practices for virtualization. For a list of Microsoft documents on virtualization, see Microsoft Virtualization: Hyper-V best practices. |
• | Install the latest Windows agent on your Hyper-V host for best performance. (If needed, upgrade the appliance first to ensure it is running an equal or later version.) |
• | To protect the file system and operating system of the Hyper-V host, you must run file-level backups. For details, see File-level Backups Overview. Any files belonging to the Hyper-V application are automatically excluded from file-level backups of the Hyper-V host. |
• | In some cases, you may want or need to protect VMs using file-level backups. For recommendations, see Protecting Hyper-V virtual machines with file-level backups. |
• | To protect a VM with both host-level and file-level (agent-based) backups, ensure that the VM's host-level and file-level jobs do not overlap. Running both simultaneously may lead to undesirable results. |
• | If recovery time objectives are important, set up Virtual machine instant recovery to quickly to spin up a failed VM from host-level backups. |
• | Full and incremental backups are supported for Hyper-V VMs. |
• | A new full backup is required in these cases: |
– | The VM configuration has changed since the last backup. This includes any configuration changes made to a VM in the Hyper-V manager, such as creating or deleting a snapshot, adding a new disk, or converting a disk from VHD to VHDX format. |
– | The VM's configuration version is not present in the last backup. |
– | The VM's configuration version has changed since the last backup. |
If the VM configuration has changed since the last backup, the next incremental fails. After this failure, the appliance promotes the next scheduled backup to a full (or displays a message indicating a full is required if an on-demand incremental is attempted). Once a full backup succeeds, subsequent incrementals run as scheduled.
• | Beginning in release 10.0, additional VM configuration version checking is used to support Hyper-V's VMCX format (introduced in Windows 2016). If you are using hosts running Windows 2016 or later, or protecting VM configuration version 6.2 or higher, see Virtual machine configuration for additional requirements. |
The following requirements must be met for host-level protection of Hyper-V virtual machines.
Item
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Description
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Hyper-V host |
The following are required for the Hyper-V host:
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Microsoft VSS |
Microsoft’s Volume Shadow Copy Service (VSS) and the Hyper-V VSS writer must be installed and running on the Hyper-V host. |
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Integration Services |
To avoid VM downtime, Unitrends recommends online backups. To perform online backups, you must install Integration Services in the guest operating system to enable the VM to create a child state snapshot. The host then uses this snapshot to perform an online backup of the virtual machine. For online backups, the following conditions must be met on the protected VMs:
If an online backup cannot be performed, the VM is temporarily put in a saved state. In saved state there is a brief downtime during the backup. |
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VMs must meet the requirements listed below. For VMs that do not meet these requirements, install the Windows agent on the VM and run file-level backups.
If the host is running agent version 10.0 or higher but the appliance is running an older version, backup and recovery jobs fail for VM configuration version 6.2 or higher. Notes:
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VM name and location |
The VM name and path to the virtual machine on the Hyper-V host must not contain escape or special characters. Backups fail if escape or special characters are present in the pathname. |
These additional requirements may apply to your environment.
Item |
Description |
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Faster incrementals for VM configuration version 5.0 and higher (2012, 2012 R2, 2016, 2019, and 2022 hosts) |
For VM configuration version 5.0 and higher, Unitrends leverages a Hyper-V changed-block-tracking (CBT) driver that greatly increases incremental backup performance. To use this driver:
Note: For Windows servers, you must enable the Hyper-V role before you install the Windows agent. If the Hyper-V role is not enabled, the CBT driver is not installed with the Windows agent.
To verify that the CBT driver was used, view backup details and look for the following in the Output: CBT DRIVER ACTION IS ENABLED. If the driver has been uninstalled or corrupted, backups complete with a warning to indicate that the CBT driver was not used. |
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Windows agent push |
To use the push feature to install the Windows agent and agent updates on the Hyper-V host, see Installing the Windows agent for additional requirements. |
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Microsoft Hyper-V Replicas feature |
Microsoft's Hyper-V Replicas feature is not compatible with the Hyper-V CBT driver. If you are using this feature, you must manually uninstall the Hyper-V CBT driver. For details, see Manually installing and uninstalling the Hyper-V CBT driver. Once the driver has been uninstalled, Hyper-V incrementals are supported but do not use the driver. The Hyper-V CBT driver is installed each time the Windows agent is installed or updated. Manually uninstall the driver as needed after updating or reinstalling the Windows agent. |
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Virtualized Active Directory servers |
To ensure database consistency, you must set up the virtualized Active Directory (AD) server in accordance with Microsoft best practices. If all Microsoft considerations are not addressed, backup and recovery of the virtual machine may yield undesired results. If you prefer not to research these best practices, it is recommended to install the agent on the VM and protect it as you would a physical server (leveraging Microsoft’s VSS writers). |
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Distributed File System environments |
Distributed File System (DFS) Namespaces and DFS Replication offer high-available access to geographically dispersed files. Because of the replication and syncing operations in DFS environments, you must set up the virtual machine in accordance with Microsoft best practices to ensure database consistency. If all Microsoft considerations are not addressed, backup and recovery of the virtual machine may yield undesired results. If you prefer not to research these best practices, it is recommended to install the agent on the VM and protect it as you would a physical server (leveraging Microsoft’s VSS writers). |
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Multi-point Services Role and RDS User Profile Disks |
Windows VMs with the Multi-point Services Role and RDS User Profile Disks are not supported. |
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Cluster shared volumes (CSVs) |
Adhere to the following requirements when using CSVs:
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Storage on SMB 2.0 shares for Hyper-V 2022/2019/2016 |
For Hyper-V 2022, 2019, and some later Hyper-V 2016 versions, additional configuration is required to protect VMs with data that resides on SMB 2.0 shares. For details, see Protecting Hyper-V 2019/2016 VMs with disks that reside on SMB 2.0 shares. |
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Storage on SMB 3.0 shares |
Unitrends can protect virtual machines with disk storage located on SMB 3.0 shares. When these VMs are backed up, the Hyper-V agent creates a VSS snapshot on the remote server and exposes it to the Hyper-V host through the SMB share pathing. The agent then backs up the VM’s files from the remote snapshot location. When the backup completes, all VSS snapshots created for the backup are removed from the server hosting the SMB share. The following are required to protect Hyper-V VMs with SMB 3.0 file storage:
The most secure option to provide all necessary access is to change the login account for the Unitrends Hyper-V agent service from bpagent to the domain administrator account. If permissions for the domain administrator do not allow access to all files for file-level backups of the Hyper-V host, run the agent as a local system account on the Hyper-V host and grant it read/write permission for the SMB shares. For instructions, see Running the Windows agent as local system account on Hyper-V server and granting account read/write permissions for SMB shares.
Example of mixed naming that causes the backup job to fail: \\HVSMBServer\Share1\WinVM\Disk1.vhd \\HVSMBServer.qatest.local\Share1\WinVM\Disk2.vhd \\192.168.199.215\share1\WinVM\Disk3.vhd Examples of consistent naming where the backup job succeeds: \\HVSMBServer\Share1\WinVM\Disk1.vhd \\HVSMBServer\Share1\WinVM\Disk2.vhd \\HVSMBServer\share1\WinVM\Disk3.vhd or \\HVSMBServer.qatest.local\Share1\WinVM\Disk1.vhd \\HVSMBServer.qatest.local\Share1\WinVM\Disk2.vhd \\HVSMBServer.qatest.local\share1\WinVM\Disk3.vhd or \\192.168.199.215\Share1\WinVM\Disk1.vhd \\192.168.199.215\Share1\WinVM\Disk2.vhd \\192.168.199.215\share1\WinVM\Disk3.vhd |