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. |
Step 3: | Add the Hyper-V host to your Unitrends appliance. See Adding a virtual host. |
Step 4: | Create backup jobs for your VMs. See Creating backup 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. |
• | To protect the file system and operating system of the Hyper-V host, you must run asset-level backups. For details, see Asset-level Backups Overview. Any files belonging to the Hyper-V application are automatically excluded from asset-level backups of the Hyper-V host. |
• | After making any configuration changes 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 VHD(X) format, you must run a new full backup to ensure the integrity of the VM’s backup groups. After running a new full back up, you can continue protecting the VM with its existing schedule. |
• | A cluster with a single cluster shared volume does not follow Microsoft’s best practices and may be unreliable. If you have VMs in a cluster with a single CSV, protect them as you would physical machines, by using asset-level backups. |
• | In some cases, you may want or need to protect VMs using asset-level backups. For recommendations, see Protecting Hyper-V virtual machines at the asset level. |
• | Do not run host-level backups for VMs that you protect at the guest OS level. Doing so can compromise log truncation changes for applications and lead to other undesirable results. |
• | If recovery time objectives are important, set up Hyper-V instant recovery to quickly to spin up a failed VM from host-level backups. |
The following requirements must be met for host-level protection of Hyper-V virtual machines.
Item |
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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Virtual machine configuration |
VMs must adhere to the following:
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These additional requirements may apply to your environment.
Item |
Description |
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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 restore 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 restore 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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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 KB 1335.
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Faster incrementals on 2012 and 2012 R2 |
Unitrends leverages a Hyper-V changed-block-tracking (CBT) driver that greatly increases incremental backup performance on 2012/2012 R2 hosts. To use this driver, simply install Windows agent version 8.1.0-3 or higher on your Hyper-V hosts. The CBT driver is automatically installed with the Windows agent. To verify that the 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. |