Using the Restore Active Directory on Clean OS method you can restore the entire forest or any of its parts on the freshly installed Windows machines. This recovery method can be used, for example, when existing BMR backups contain the infected OS image. In this case, Active Directory backups can be used due to they do not contain binaries (except Sysvol files). Active Directory backups can be also checked for viruses.
Domain controllers that are running on virtual machines in Amazon Web Services (AWS) or Microsoft Azure can be restored with the Restore Active Directory on Clean OS method.
NOTE |
The first step of the Restore Active Directory on Clean OS recovery method is to promote the selected Windows server to a domain controller. This operation cannot be performed for Windows Server 2012 R2 or higher machines with FRS replication. So, Restore Active Directory on Clean OS is supported only for Windows Server 2012 R2 or higher with DFS Replication. |
At the first stage of the Restore Active Directory on Clean OS recovery method, the DNS server role is installed on a domain controller. For this reason, it is recommended to use a backup that was made on the AD-integrated DNS server for Clean OS recovery. You can still use backups that were made on the non-AD-integrated DNS server but in this case you should not use Automatic DNS selection option on any domain controller in such a domain.
If your domain has AD-integrated DNS servers restored from backup, you need to specify the DNS settings manually. After recovery, the domain controller that was restored by the Restore Active Directory on Clean OS recovery method synchronizes DNS partitions and continues to be a DNS server.
If your domain uses external DNS, you need to specify the DNS settings manually for every domain controller in the domain. After recovery, the domain controller restored by the Restore Active Directory on Clean OS recovery method will run a non-functional DNS server so you can uninstall it.
If you are testing Forest Recovery in the lab environment and your production forest uses an external (non-AD integrated) DNS server.
You can prepare the lab by installing a new DNS server (e.g. on the RMAD server).
Create empty DNS zones on this server in accordance with your production DNS configuration.
Ensure that SOA and NS records created in the empty zone have the FQDN DNS name corresponding to this DNS server.
Create an A record pointing to this server IP address in each zone.
Ensure that non-secure DNS dynamic updates are enabled.
A blank host should comply with the following requirements:
The version of the Windows operating system must match the version deployed on the failed domain controller.
A blank host must have the same drive letters as the source domain controller if the Use AD paths from backup check box is selected or the drive letters must match the custom paths specified in the project.
A blank host should have enough free space for AD and SYSVOL data.
The account that is specified in Forest Recovery Console to access the target blank host should be the local Administrator on this machine.
Recovery Manager for Active Directory promotes the selected Windows server to a domain controller and then restores Active Directory data.
You can use the Forest Recovery Console to create a virtual machine in Microsoft Azure Active Directory. You can then use the Restore Active Directory to Clean OS recovery method to restore Active Directory on the virtual machine.
Create Active Directory backups
Create a recovery project
To create a virtual machine in Microsoft Azure
In the Forest Recovery Console, create a new project or select an existing recovery project.
Select the Domain Controller to be created as a virtual machine in Azure.
From the Recovery Method drop-down list, select Restore Active Directory on Clean OS.
In the Server access credentials section, type the user name and password that you want to be created as a local account on the new virtual machine in Azure. These credentials are used during the Forest Recovery process.
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You cannot use 'Administrator' in the Local user name field as this name is reserved in Azure. |
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The backup file must be accessible from both the Forest Recovery Console server and the newly created DCs in the Azure virtual network. For example, backup may be located on Azure File Share or access to backup files located on premise from the Azure virtual network may be configured by setting up a Site-To-Site VPN connection. |
On the Infrastructure tab, from the Infrastructure drop-down list, select Microsoft Azure.
Click Edit to configure the infrastructure template and virtual machine settings.
In the Recovery Project Settings window, on the Infrastructure tab, click Login to sign in to the Azure tenant. Provide a user account that is assigned an Azure role with create and write permissions for the required resource group and all other virtual machine resources. The Azure built-in role of Owner or User Access Administrator on the subscription is recommended.
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To create a virtual machine in Azure, the Az Powershell module is required. If the module fails to install automatically, click the link provided to download and install the module manually. After installation, click refresh to update the information on the Infrastructure tab. |
After successful login, the fields on the Infrastructure tab are populated with information retrieved from the tenant. This includes available subscriptions, resource groups, networks, and security groups. If the resource already exists in the selected Azure subscription RMAD will not create a duplicate. This reuse of resources is recommended for performance of your restore operation.
From the Subscription drop-down list, select the subscription to be used by the infrastructure template.
In the Infrastructure Settings section, configure the following settings:
To manually assign a static IP address for the virtual machine to be created in Microsoft Azure select the Manually assign a static IP address in the subnet's address range checkbox. After the template settings are configured and the Azure template is applied to domain controllers, click the Infrastructure tab for the domain controller, under Target Virtual Machine. Type a valid IP address within the sub-network IP range for the virtual machine in Azure. When the virtual machine (Domain Controller) is created in Azure, the IP address will be statically assigned.
IMPORTANT |
The Virtual Network Gateway(VPN connection) will take approximately 30 minutes to be created. If Connect VMs using Virtual Network Gateway (VPN Connection) and Delete Infrastructure after verification are both selected, the Virtual Network Gateway will be deleted as part of the infrastructure. Since the Virtual Network Gateway will need to be created again during the restore operation, the length of time required for the recovery will be increased by 30 minutes. |
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If unused resources are not deleted, this may incur additional cost for your tenant. |
In the Virtual machine Settings section, configure the following settings:
Virtual machine name: Type a name for the virtual machine or use the {DnsName} template.
Overwrite the VM if exists: Select this check box if you want the new VM to overwrite an existing one with the same name.
Delete VM after verification: Select this check box to delete the virtual machine after the Verify Settings process is complete. This is useful for testing purposes or if the machine is expected to be unused and to manage cost. The check box is automatically selected when the Delete infrastructure after verification is selected. If a recovery process is started, the machine is recreated.
Virtual machine size: Select the instance type for the virtual machine size that you want based on the number of CPUs and amount of memory. A full list of all available instance types is provided for selection.
Auto select virtual machine size: Select this check box to have the virtual machine size automatically selected based on the original domain controller configuration. When automatically selecting the virtual machine size, Recovery Manager for Active Directory uses the Microsoft Azure Virtual Machine D-series for general purpose computing. The number of cores is then read from the backup and the closest match found. For cost efficiency the smallest available memory size is selected.
Storage type: Select the storage type. This affects performance.
Disk size: Select Use Original Sizes for the disk size to be determined by the size of the Active Directory data size (DIT, LOGS, SYSVOL) in the back up. Select Set Size to customize the size of the disk for the virtual machine.
^{note} The disk will have a minimum size (128 GB for an operating system disk and 8 GB for a data disk). If the selected disk size is not large enough for the restored data, the system will use the required size and this setting will be ignored.
Click Apply then click OK.
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If the signed in user does not have sufficient permissions to create or write the resource group and resources, an error message will be displayed. If the user was recently granted permissions for the resource group, please refresh the credentials in the Recovery Project Settings window. |
A service principal containing the settings you configured is created for the connection to Azure.
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After you have configured the default infrastructure template named "Microsoft Azure", you can then clone the default template. That is, you can create a new template based on the Azure template and apply it to other DCs in the Forest Recovery project. |
To start recovery of Active Directory to Microsoft Azure virtual machines
During recovery, the Active Directory backups of the domain controllers defined in the recovery project will be restored to newly created virtual machines in Microsoft Azure.
Active Directory failure, which includes corrupted, completely lost, or unbootable domain controllers, is something that scares any administrator. There can be a lot of reasons for the loss of valuable data. It can be caused by any error, a virus, or a natural disaster. With our disaster recovery plan, you get an insurance policy for your business information.
This section contains recommendations for recovering an Active Directory forest if forest-wide failure renders all domain controllers (DCs) in the forest incapable of functioning normally.
NOTE |
Domain controllers that are running on virtual machines in Amazon Web Services (AWS) or Microsoft Azure cannot be restored with the Bare Metal Active Directory Recovery method because there is no way to boot such DCs from an ISO image. |
If you do not want to encrypt BMR backups, we recommend that you enable the Server Message Block (SMB) Encryption feature (SMB version 3.0 and higher ) on the network share to secure network connection. For more details on how to turn on SMB Encryption, see https://docs.microsoft.com/en-us/windows-server/storage/file-server/smb-security. Note that backed up domain controllers must support SMB Encryption as well.
The best practice is to store backups in the repository that is located in the same Active Directory site due to faster network.
For Windows Server 2008 R2, BMR backups that are stored on the Forest Recovery Console host are not supported.
The account that is used to access the BMR backups location must have Read and Write permissions for that location.
If the process of creating a Windows Server 2008 R2 BMR backup completes with an error similar to "The sector size of the physical disk on which the virtual disk resides is not supported", make sure that the disk sector size on the target machine (NAS device or similar) is equal to 512 bytes. For instance, NetApp ONTAP operating system uses the following command: vserver cifs options modify -file-system-sector-size 512
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Active Directory does not allow the use of a backup with an age that exceeds the Active Directory tombstone lifetime (default is 180 days). But if there is a RMAD BMR backup that is older than 180 days and a more recent Active Directory backup, you can successfully perform the restore operation.
The number of physical disks on the target computer must be equal to or exceed the number of critical disks on the source machine at the time the backup was created. A critical disk contains critical volumes (volumes that contain the operating system's state).
The order of system partitions must be the same on the target disk as on the source one.
The physical disks on the target computer must be of the same size as the critical disks or larger.
If a source machine with the legacy BIOS firmware has physical disks of different sizes, it is critical to have the same physical disks order on the target machine. For example, if a source has two disks - disk 0 (90 GB), disk 1 (40 GB), the target should have the same 90-40 order.
The firmware on the target computer must be compatible with the configuration of the source disks.
If the physical disks on the source computer have the GPT partition style, the target computer must have UEFI firmware and must be booted in the UEFI mode.
If the physical disks on the source computer have the MBR partition style, then the target machine should be booted in the BIOS-compatibility mode (or just legacy BIOS mode).
Source partition style | BIOS (Target firmware) | UEFI (Target firmware) |
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GPT | Incompatible | Compatible |
MBR | Compatible | Compatible (legacy BIOS-compatibility mode) |
It is recommended that you encrypt your Bare Metal Recovery backup by selecting the Encrypt and protect backups with password option (by default, this option is disabled) on the Backup tab in the collection properties. For details, see Creating BMR and Active Directory backups. In this case, not only the backup data stored on the remote share is encrypted, but the data transferred over the network during the backup operation is encrypted as well.
If Active Directory backup encryption is enabled, the RMAD BMR backup will be encrypted by BitLocker. Recovery Manager for Active Directory uses a virtual hard disk encrypted by BitLocker as a container for the backup (256-bit AES encryption).
An encryption key for the backup is derived from the backup password and is not tied to a TPM chip (if any). This means that the encrypted RMAD BMR can be used on another machine, without or with another TPM chip. Only a backup password is required.
The BitLocker Drive Encryption feature should be installed on all backed up domain controllers and on the Forest Recovery Console machine to support encrypted BMR backups. But note that the BitLocker feature does not encrypt DC drives automatically. After the feature is installed, it is required to reboot the machine.
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After disaster recovery, volumes on the restored machine will not be BitLocker-protected. You must enable the BitLocker protection again, if required. |
To enable backup encryption, see Enabling backup encryption.
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