FSMO…
Active Directory is like a huge database, sync’d across a potentially huge number of different Domain Controller server in your environment. In an environment with lots of DCs spread across numerous sites, the potential for change conflict is huge.
What if DC1 in Redmond receives a change and needs to sync it around the entire domain… In the early days of Active Directory, there was one single master domain controller server, known as the Primary Domain Controller (PDC), that was responsible for making all changes like this.
Technically, the PDC role no longer exists but some of the same protections are still in place under the hood – Flexible Single Master Operation (FSMO) roles.
Every instance of Active Directory has FSMO roles and FSMO role holders.
Here are the five FSMO roles:
1. Schema master
2. Domain naming master
3. RID master
4. PDC emulator
5. Infrastructure master
Creating new servers and turning them into Domain Controller is technically known as promoting those servers to become Domain Controllers.
Conversely, removing a DC from your environment is known as demoting.
to be continued…