Recommended practices for FSMO roles

Microsoft has published the following recommendations as part of Knowledge Base article 223346 (https://support.microsoft.com/en-us/help/223346):

• Place the schema master on the PDCe of the forest root domain.
• Place the domain naming master on the forest root PDCe.
• Place the PDCe on your best hardware in a reliable hub site that contains replica domain controllers in the same Active Directory site and domain.
• Place the RID master on the domain PDCe in the same domain.

For a single domain in a single forest with the Active Directory Recycle Bin optional feature enabled, this means that all five FSMO roles can best be placed on one domain controller.

For an Active Directory forest with multiple domains, it means the forest-wide Schema Master and Domain Naming Master FSMO roles can best be combined with the PDCe and RID Master roles for the forest-root domain on one domain controller. For every other domain, the PDCe and RID Master roles are to be placed on a domain controller per domain. Whether or not the Infrastructure Master FSMO role plays any part depends on the Active Directory Recycle Bin.

This might not be the situation in every Active Directory environment, indicating the need to manage the FSMO roles.