# System requirements for Active Directory forest recovery

Verify that the domain controllers you install the Commvault software on meet the following system requirements.

## Domain controllers

### Operating system

- Windows server 2025

- Windows Server 2022

- Windows Server 2019

- Windows Server 2016

### SYSVOL replication

Active Directory forest recovery is supported only for domains that use Distributed File System Replication (DFSR) for SYSVOL replication. Domains that use File Replication Service (FRS) for SYSVOL replication are not supported, as Microsoft has deprecated FRS for SYSVOL replication.

Forest recovery requires DFSR-based SYSVOL replication to ensure consistent and supported recovery behavior. To determine the SYSVOL replication method, run the following command on the Primary Domain Controller (PDC):

`dfsrmig /getglobalstate`

- If the output shows a global state of 3 (Eliminated), the domain is using DFSR and is supported.

- If the domain is in any other state, or if FRS is in use, migrate SYSVOL replication to DFSR before deploying Active Directory forest recovery.

### Commvault agent and full System State restore

For domain controllers configured to use the Recover to new VM (full system state) option, the Commvault agent used for forest recovery must be the first instance of the agent (for example, Instance001) on that server. Otherwise, the VirtualizeMe restore will fail.

If there is an agent installed on the domain controller from another instance of Commvault, you must uninstall it before installing the agent that will back up the domain controllers for forest recovery or use another recovery method such as Recover AD to clean VM database only.

## Recovery node

The recovery node manages tasks in the forest recovery runbook, coordinating domain controller recovery jobs and executing pre- and post-configuration steps. For information on system requirements for recovery nodes, see System Requirements for On-Premises Backup Gateways.

### Recovery options that automatically provision VMs

Recovery options that automatically provision VMs require the appropriate network access to push software installation to the target VM.

- For Azure and AWS targets: The required ports must be open in both the Network Security Group (NSG) and on the target VM.

- For Hyper-V and VMware targets: The required ports must be open, and the necessary configuration must be applied to the provided VM template.

The network configuration includes:

- Port 135 for DCOM (Distributed Component Model)

- Port 139 for NetBIOS Session Service, if in use

- Port 445 for SMB (Server Message Block) file sharing

- WMI (Windows Management Instrumentation) port

- Ports 49152–65535 for dynamically allocated RPC ports (or configured RPC dynamic range)

- Additional Windows Firewall rule configuration may be required

For more information on network requirements and instructions, see Prerequisites for Installations Using the CommCell Console.

#### Hard drive

Enough space to recover the total size of all the source DCs + 50 GB or more

#### Memory

Enough space to host the recovered DCs + 8 GB or more

#### Recovery target

The recovery target is the hypervisor configured to host domain controllers that are restored in an out-of-place recovery. Out-of-place recovery methods restore domain controllers to newly provisioned virtual machines and require sufficient compute, storage, and network resources to host the recovered environment.

In-place recovery methods restore Active Directory on the original domain controller and do not require a recovery target. To use in-place recovery methods, the source domain controller must remain available and accessible during the recovery operation. In-place recovery is intended for scenarios where the operating system remains functional and trusted, such as schema corruption, database corruption, or unwanted Active Directory changes.

## Domain Name System (DNS)

The default forest recovery runbook configuration assumes that Active Directory-integrated DNS is deployed in the environment. Forest recovery also supports environments that use external DNS services or DNS appliances. When external DNS is used, configure the runbook to use the external DNS server and complete the required DNS validation steps during recovery. For more information, see Domain Name System (DNS) considerations.

## File system agent requirements

The file system agent is automatically installed during the installation of this software, if it is not already installed.

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