Does the FSMO role need to be transferred before being demoted?

Question

I have 2 DC’s. The DC holds the FSMO (Flexible single master operation) role in Windows Server 2016. Before I demote the primary DC Windows Server 2016 to install Windows Server 2019, do I need to transfer the FSMO role to the secondary DC, or will the other DC automatically take over these roles?

Answer

When you demote a domain controller that is a role holder, the FSMO role will automatically transfer to another domain controller. As a best practice, I personally prefer to transfer the roles myself before demoting, just to ensure that everything is healthy.

Run the following command to check the FSMO holder: netdom query fsmo