Planning Operations Master Locations

When you create the first domain in a new forest, all of the operations master 70-680 roles are automatically assigned to the first domain controller in that domain. When you create a new child domain or the root domain of a new domain tree in an existing forest, the first domain controller in the new domain is automatically assigned the RID master, PDC emulator, and infrastructure master roles. Because there can be only one schema master and one domain naming master in the forest, these roles remain in the first domain on the first domain controller created in the forest.
The default operations master locations work well for a forest deployed on a few domain controllers in a single site. In a forest with more domain controllers, or in a forest that spans multiple sites, you need to transfer the default operations master role assignments to other domain controllers in the domain or forest to Balance the load among domain controllers, or Accommodate domain controller maintenance and hardware upgrades

Schema Master Failure Temporary loss of the schema operations master is not visible to network users. It is not visible to network administrators either, unless they are trying to modify the schema or install an application that modifies the schema during installation. If the schema master will be unavailable for an unacceptable length of time, you can seize the role to the domain controller you've chosen to act as the standby schema master. However, seizing this role is a step that you should take only when the failure of the schema how to get windows 7 for free master is permanent.
Domain Naming Master Failure Temporary loss of the domain naming master is not visible to network users. It is not visible to network administrators either, unless they are trying to add a domain to the forest or remove a domain from the forest. If the domain naming master will be unavailable for an unacceptable length of time, you can seize the role to the domain controller you've chosen to act as the standby domain naming master. However, seizing this role is a step that you should take only when the failure of the domain naming master is permanent.

RID Master Failure Temporary loss of the RID operations master is not visible to network users. It is not visible to network administrators either, unless they are creating objects and the domain in which they are creating the objects runs out of relative identifiers. If the RID master will be unavailable for an unacceptable length of time, you can seize the role to the domain controller you've chosen to act as the standby RID master. However, seizing this role is a step that you should take only free Microsoft practice IT questions when the failure of the RID master is permanent.