Disaster Recovery - Failed DC with no backup

Question

Hi...asking for advice on rebuilding the DC/Domain setup in a small single site & server business.

A friend of mine's come asking for my help after the DC in his single server & single site business failed as he hadn't noticed the failed disks before it was too late.

To add insult to injury, he had neglected his backups. doesn't have any backup of the server of which was 2003 Small Business Server with W7/W10 Clients

He has been able to get a DR firm to recover the data from the RAID on the 2003 box.

Short of building a new domain for him and adding two new servers to it, moving the recovered data onto them and rebuilding apps from suppliers.

Is there a way to demote the old failed non-contactable DC and then promote the new 2019 server as a DC (making the second 2019 server a backup DC)?

Thanks

Answer 1

Hello

Thanks for posting in Microsoft Community.

Although recovery in this case is tricky, there are still ways to rebuild the domain controller and domain without having to start from scratch. Here are the specific recovery steps.

1. Set up a new domain controller

You mentioned that you would use Windows Server 2019 as the new DC, which is a good choice. You can achieve this by following the steps below:

1.1 Install Windows Server 2019

First install Windows Server 2019 on the new server.

1.2 Join the new server to the domain

If the old DC is still running (although it is not available, but it is still online), you can try to join the new server to the domain with the existing domain administrator credentials.

If the old DC is completely down and cannot be accessed, you can choose to create a new domain (without using the original domain data).

1.3 Promote the new server to a domain controller

Open Server Manager > Add Roles and Features.

Select the Active Directory Domain Services (AD DS) role and install it.

After the installation is complete, open the wizard and select Add a domain controller to an existing domain.

Enter the domain administrator credentials and follow the prompts to complete the process of promoting to a domain controller.

During the promotion process, you can also choose to configure the new DC as a Global Catalog Server (GC) and DNS Server.

2. Clear the old DC that is dead

If the old Windows Server 2003 DC has completely failed and cannot be accessed, you need to remove the metadata of the old DC to avoid affecting the normal operation of the new domain controller.

2.1 Use ntdsutil to remove the old DC

On the newly created 2019 DC, open the Command Prompt as an administrator.

Enter the ntdsutil command to enter the ntdsutil tool.

Use the following command to clear the metadata of the old DC:

ntdsutil

metadata cleanup

remove selected server

quit

This will remove the old, dead DC from the metadata of Active Directory to prevent it from affecting the new DC.

2.2 Force replication

Open Active Directory Sites and Services.

Make sure the new DC can replicate with other servers to ensure that updates to the domain are propagated.

3. Recover Data

Since the RAID data has been recovered, the next step is to recover files and application data.

3.1 Transfer Files and Data

Copy the recovered user data, shared files, etc. to the new server to ensure that user data and file shares have been restored.

3.2 Recover Applications

For applications (such as email, financial management, etc.), you need to reinstall and configure these applications on the new server.

If there is recovery data or configuration files from the old server, you can try to restore these configurations.

4. Configure a backup domain controller

When the new DC is set up and the data recovery is complete, you can set up the second Windows Server 2019 server as a backup domain controller (BDC) to ensure domain controller redundancy.

4.1 Install the second Windows Server 2019

Install Windows Server 2019 on the second server.

Join the second server to the existing domain (if it has not yet been joined).

Promote the second server to a domain controller. This will serve as a backup for the primary DC.

4.2 Configure DNS and Global Catalog

Ensure that the second DC is configured as a Global Catalog Server and DNS Server to improve the fault tolerance of the system.

I hope the above information is helpful to you.

Best regards

Runjie Zhai