Preparing for instant recovery
Unitrends recommends planning for instant recovery before a VM fails. Following is a summary of the steps needed to set up instant recovery for your virtual machines. Steps include links to detailed instructions for each procedure.
Step 1: | Ensure that all requirements have been met. For details, see Prerequisites for VMware instant recovery or Prerequisites for Hyper-V instant recovery. |
Step 2: | Run host-level backups of the VMs: |
• | To create a job manually, see To create a VMware backup job or To create a Hyper-V backup job. |
• | To create a job by using an SLA policy, see To create an SLA policy for VMware assets or 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. |
Step 3: | Reserve space on the appliance for instant recovery. For details, see Allocate storage for instant recovery. |
Step 4: | Add target virtual hosts to the Unitrends appliance as needed. |
While running the IR procedure, you select a virtual host where the recovered VM will be created. You can recover to the host where the original VM resides or to a different location. If needed, add additional virtual hosts to the appliance to make them available for IR. For details, see Adding a virtual host.
Note: For VMware, a vCenter is required. Add the ESXi hosts and the vCenter managing the hosts.
Step 5: | Run IR in audit mode to check the recovered VMs. For details, see Perform instant recovery in audit mode. |

The following table describes prerequisites and considerations for VMware instant recovery.
Prerequisite or consideration |
Description |
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vCenter version and license |
To perform instant recovery, the ESXi server used as the instant recovery target must be managed by a vCenter that meets the following requirements:
Note: You can perform the audit process using a stand-alone ESXi server, but instant recovery mode is not supported. |
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ESXi server |
The ESXi server used as the instant recovery target must meet the following requirements:
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Backup |
You must have a backup to recover a virtual machine. The backup used for the instant recovery must be:
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The following configuration settings apply to the recovered VM:
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The following table describes prerequisites and considerations for Hyper-V instant recovery.
Prerequisite or consideration |
Description |
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Hyper-V server |
Unitrends recommends reloading the list of VMs on the appliance after installing the agent on the host Hyper-V servers. To reload the list of VMs, select Options > Inventory Sync.
Note: Backups from older versions of Hyper-V can be used for Hyper-V instant recovery as long as the target server is running 2012 or a higher version listed in the Compatibility and Interoperability Matrix.
To modify the number of simultaneous storage migrations, open Hyper-V manager, right-click the host server and select Properties, select Storage Migrations and modify the Simultaneous storage migrations setting:
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Backup |
You must have a backup to recover a virtual machine. The backup used for the instant recovery must be:
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The following VM configuration settings and requirements apply to the recovered VM:
Note: Not all VM settings are preserved during instant recovery. Review the list of preserved and non-preserved settings to determine if instant recovery is the best approach for your VM. VM settings preserved during instant recovery:
VM settings NOT preserved during instant recovery:
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Cluster requirements |
Hyper-V instant recovery supports clustered and non-clustered virtual machines. The following requirements must be met to recover a clustered VM:
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Instant recovery can be performed at any time, as long as there are backups or backup copies for your VMs and sufficient backup storage is allocated as instant recovery space. Unitrends strongly recommends reserving space for instant recovery soon after initial deployment and before a VM fails. If necessary, you can allocate instant recovery space later, but doing so may require the appliance to purge local backups to make room for the newly allocated instant recovery space.
Because the disks for a recovered VM reside on the appliance until storage migration completes, you must allocate a portion of your backup storage for instant recovery. You must allocate at least 20 percent of the space used on the VM’s original disks. Once disks have been migrated to the recovered VM, appliance instant recovery storage is no longer needed.
Notes:
• | Appliance storage that is allocated to instant recovery can also be used for the Windows replica feature. |
• | Storage allocated for instant recovery cannot be used for backups. |
• | Recovery Series and Recovery MAX physical appliances come with a set amount of backup storage. Backup storage allocation can be modified to increase the amount used for instant recovery. Backup storage cannot be added to the appliance. |
• | Unitrends Backup virtual appliances are deployed as virtual machines. After initial deployment, you can add more backup storage as desired. For details, see About adding backup storage to a Unitrends Backup appliance. |

1 | On the Configure > Appliances page, select the appliance. |
2 | On the Storage tab, select the Internal storage and click Edit. |
3 | Modify the percentages used for backups versus instant recovery, and click Save. |

Perform instant recovery in audit mode to verify that backups and backup copies can be used to recover the VM in the event of a disaster. Repeat this procedure as needed to test new backups.

Run this procedure from the backup appliance to recover from a backup or imported backup copy. Run this procedure from the backup copy target appliance to recover from a hot backup copy.
1 | Log in to the backup appliance or target appliance (if recovering from a hot backup copy). |
2 | Select Recover and click the Backup Catalog tab. |
(Optional) Use Filter Backups to the right to customize the backups that display. For details, see Working with custom filters.
3 | Expand the VM asset and select one of the following to use for the recovery: |
• | A host-level backup. |
• | An imported host-level backup copy. (To import a backup copy, see To import a cold backup copy or To import a hot backup copy.) |
• | A hot backup copy (supported if performing IR on the target appliance where the hot copy resides). |
4 | Click the Instant Recovery button. |
5 | Check the Recover this VM in Audit Mode box. |
6 | Select the following Recovery Options: |
Recovery Options |
Description |
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Target Location |
Select the host where the VM will be recovered. The list contains hosts that have been added to the appliance and are compatible with the VM being recovered. Incompatible hosts do not display in the list.
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Target Resource |
(Optional) Select a resource pool. This field displays only if the Target Location is an ESXi host that has resource pools. |
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Target Storage |
Select a datastore (ESXi host) or volume (Hyper-V host). |
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Target Appliance Network |
Select a network adapter on the appliance to use for the recovery. eth0 is selected by default. If your appliance is configured with multiple adapters, you can opt to select a different adapter from the list. The appliance uses the selected adapter for communication with the hypervisor during the storage migration. |
7 | Click Next. |
8 | Review the recovery settings. |
• | A recovered VMware VM is created with the following default name: <original_VM_name>_restore. To change this name, click the pencil icon. |
• | A recovered Hyper-V VM is created with the same name as the original VM and no suffix. Due to Hyper-V limitations, it is not possible to rename the VM during the recovery, and the original VM is overwritten by the recovery operation if it resides on the recovery target. |
9 | Click Save to start the recovery. |
10 | Click OK to close the Information message. |
The recovered VM is created on the target host. The VM has no network settings.
11 | Check IR progress by viewing details on the Instant Recovery tab. |
Note: If you are recovering an incremental that has a long chain of dependent incrementals, it can take extra time to create the recovered VM.
• | Click the Instant Recovery tab. Active IR sessions display by VM name. |
• | Click to select the IR session you created. |
• | Click View Details above. |
• | Status messages display in the Details tab below. IR moves through several phases. The VM can be accessed when you see this message: VM is available for use. |
12 | Access the VM directly from the target VMware or Hyper-V host. Log in to the VM console and verify that the recovered VM is functioning as expected. |
Notes:
• | Any features or applications that require network access do not have full functionality in audit mode. |
• | Any changes made to the recovered VM in audit mode are lost when you tear down the IR session. These changes are not applied to the production VM that you are auditing. |
• | Windows server VMs - In rare instances, after a restore is performed for a Windows server VM, a disk may be inaccessible because it has been placed in an offline state. To bring disks into an online state, login to the VM, go to Disk Management, right-click on the offline disk, and select Online from the drop-down menu. |
• | Debian VMs - In some instances, Gnome might not start after a Debian VM is recovered. You can resolve this issue by rebooting the VM or restarting Gnome from the console. To access the console, enter Ctl+Alt+F1 and log in as root. Then run startx. |
13 | Tear down the IR session: |
• | On the Instant Recovery tab, click to select the IR session. |
• | Click Tear Down. |
• | Click Confirm. |
The recovery object is removed from the appliance and the recovered VM is removed from the target host.